CZ288371B6 - Structure for transport of liquids and process for producing thereof - Google Patents

Abstract

The invented structure is provided with a first surface (90) and a second surface (85) in which there are performed passages (71) for passage of fluid between the first surface (90) and the second surface (85), whereby the structure is formed by a shaped sheet and is further provided with volcano-like surface irregularities. Surface energy gradient are defined by regions (98), which are adapted for applying force to fluid being in contact with the first surface (90) so that fluid is directed toward the passages (71) for transporting fluid away from the first surface (90) toward the second surface (85), whereby the regions (98) contain material being selected from a group comprising silicon releasing coatings, treated silicon material, fluorinated materials, petrolatum, latexes, paraffins, surface-active agents and wetting agents.

Description

Structure for transfer of liquids and process for its production

Technical field

The present invention relates to a structure suitable for use as a fluid transport mechanism. In particular, the structure is designed to facilitate fluid transport in a preferred direction from one surface to another and to resist fluid transport in the opposite direction.

BACKGROUND OF THE INVENTION

In the field of the production of disposable absorbent articles, it has long been known that it is exceptionally desirable to assemble absorbent devices such as disposable diapers, sanitary napkins, incontinence briefs, wound dressings and sores and the like to provide the wearer with a dry surface for enhanced comfort. and minimizing the potential for undesirable skin conditions due to prolonged exposure to moisture absorbed within the product. Accordingly, it is generally desirable to promote rapid fluid transport in the direction from the wearer and into the containment structure, while preventing fluid transport in the reverse direction. One viable solution to the above prior art problem has been applied to the exposed, contacting, surface area, cover or topsheet, which comprises a molded, aperture (aperture) thermoplastic film structure. U.S. Pat. No. 4,342,314 discloses an exemplary molding film of this kind. These structures utilize capillary fluid transport to direct fluid from one surface (the wearer contacting) into the structure through three-dimensional capillaries formed into a particular material and then into the underlying absorbent structure. In order to address consumer concerns with respect to plastic design and feel, structures of this kind have been developed which include an interconnected fabric appearance structure in order to create a more fabric, aesthetically acceptable appearance. In addition, aperture, molded thermoplastic film structures have been developed that further comprise a microscopic surface texture (microtexture) and / or microscopic apertures (microapertures or micro-holes) to further enhance the visual and tactile impression of these structures. Exemplary films of this type are disclosed in U.S. Patent Nos. 4,463,045, and 4,629,643. One more prior art solution was to use fibrous material as a cover or topsheet on these products alone or as a cover or laminate over other materials. An exemplary topsheet structure of this kind is disclosed in PCT application WO 93/09741. These fibrous materials may take the form of a woven or non-woven structure of a suitable fiber type, or may not contain discrete-formed apertures themselves, in addition to the inherent porosity of the structure. Structures of this kind also exhibit capillary fluid transport characteristics through three-dimensional capillaries, formed by inter-fibrous gaps, similarly conveying fluid away from the wearer of the contacting surface and into the underlying absorbent structure. These structures exhibit an aesthetically attractive, fabric surface appearance and tactile sensation due to the fibrous nature of their surface.

Although the capillary structures of the previous species are effective in fluid transport, their effectiveness is limited in that these capillary structures can only move fluid once they have entered the capillary. Fluid that moisturizes and remains on the wearer contacting surface contributes to a " wet " feel or impression, and to the extent that the fluid may be discolored or opaque also contributes to a " stained " visual impression. The surface textures naturally occurring in the material of the structure, or imparted to it during molding, further increase the likelihood that residual fluid will be attached or retained in the wearer contacting surface rather than entering the capillary structures when carried away from the surface. Thus, surface topographies that contribute to desirable visual and tactile impressions when dry may also tend to retain residual fluid on the exposed surface and be less desirable in user conditions.

-1GB 288371 B6

Accordingly, it would be desirable to provide a structure with enhanced fluid transport efficiency from that surface that is initially contacted with some fluid.

In particular, it would be desirable to maintain the visual and tactile properties of structures with fibrous or otherwise textured surfaces, while promoting faster and more complete fluid transfer from the surface of the contacting wearer and to the interior of the composite absorbent article.

SUMMARY OF THE INVENTION

The liquid transfer structure of the present invention is provided with a first surface and a second surface. In this structure, fluid flow passages are formed between the first surface and the second surface, the structure being formed by a shaped film and further provided with volcanic surface variations. The structure of the invention has surface energy gradients which are defined by regions that are adapted to exert a force on the fluid in contact with the first surface such that the fluid is directed towards the passages for discharging it from the first surface to the second surface. The regions comprise materials selected from the group of silicone release coatings, treated silicone material, fluorinated materials, petrolatum, latexes, paraffins, surfactants and wetting agents.

According to a preferred embodiment, the regions are arranged at a discontinuous spacing from one another and are located at least partially within the fluid passageways.

According to another preferred embodiment, the regions are distributed irregularly on the first surface.

The first surface has a first surface energy and the second surface has a second surface energy that is higher than the first surface energy.

The surface energy gradients are delimited by the boundaries between said regions and materials having different surface energy characteristics.

According to another preferred embodiment, the regions are coated with curable silicone as a low surface energy material.

It is further preferred that the volcanic aberrations are provided with at least one micro-hole.

The shaped film is formed by a multilayer film having a first layer and a second layer, the second layer having a higher ductility than the first layer and having a higher surface energy than the surface energy of the first layer.

A liquid transfer structure having a plurality of surface energy gradients is produced by first forming a plastic film having a first layer and a second layer, a first layer having a first ductility and a first surface energy, and a second layer having a second ductility that is higher than a first ductility and a second surface energy that is higher than the first surface energy, then the plastic film is fed to the molding structure, the plastic film is subjected to a pressure difference, which adapts the plastic film to the molding structure and breaks to form a discrete fluid passageways associated with the first surface and the second surface, wherein by forming these fluid passages the first layer abuts the first surface and the second layer abuts the second surface.

-2GB 288371 B6

BRIEF DESCRIPTION OF THE DRAWINGS

Although the description is terminated by the claims specifically indicating and clearly claiming the present invention, it is believed that the invention will be better understood from the following description taken in conjunction with the accompanying drawings, of which:

Giant. 1 is an enlarged, partially segmented, perspective view of a prior art plastic structure type generally disclosed in U.S. Patent No. 4,342,314.

Giant. 2 is an enlarged, partially segmented, perspective view of a preferred plastic structure of the present invention having a surface energy gradient.

Giant. 3 is an enlarged cross-sectional view of a fluid drop on a rigid surface, wherein angle A shows the angle of contact of the fluid with the rigid surface.

Giant. 4 is an enlarged cross-sectional view of a liquid drop on a rigid surface having two different surface energies, thus showing two different contact angles A (a) and A (b).

Giant. 5 is an enlarged cross-sectional view of a fluid drop located adjacent a generic capillary having a surface energy gradient.

Giant. 6 is another enlarged, partial view of the structure of FIG. 2 showing one embodiment of the present invention.

Giant. 7 is a further enlarged, partial view of the structure of FIG. 2 showing an alternative structure of the present invention.

Giant. 8 is an enlarged, partially segmented, perspective view of another embodiment of the nonwoven web of the present invention.

Giant. 9 is a further enlarged, partial view similar to FIG. 6 of the nonwoven web of FIG. 8.

Giant. 10 is a greatly enlarged, simplified schematic representation similar to that of FIG. 2, " macroscopically expanded ", microscopically aperture three-dimensional structures exhibiting a surface energy gradient according to the present invention.

Giant. Fig. 11 is another enlarged, partial view similar to Fig. 6 of the structures of Fig. 10.

Giant. 12 is an enlarged cross-sectional view of the structures of FIGS. 10 and 11, but show more detailed details of the orientation of surface energy gradients relative to the structure.

Giant. 13 is a view generally similar to FIG. 9, but to another embodiment of the composite structure of the present invention.

Giant. 14 is a plan view of a sanitary napkin having cut off portions for easier depiction of its assembly.

Giant. 15 is a cross-sectional view of the sanitary napkin of FIG. 14, taken along section line 15-15.

Giant. 16 is a plan view of part of an embodiment of the topsheet of a sanitary napkin made in accordance with the present invention.

-3GB 288371 B6

Giant. 17 is a plan view of a portion of the topsheet of yet another embodiment of a sanitary napkin made in accordance with the present invention.

Giant. 18 is an enlarged, partially segmented, perspective view of a representative diaper absorbent article made in accordance with the present invention.

Giant. 19 is an enlarged, perspective view of a representative absorbent article in a similar sanitary napkin or sanitary napkin made in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Giant. 1 illustrates an enlarged, partial, segmented perspective view of a flexible, three-dimensional, fluid-permeable plastic structure 40 of the prior art, having a combination of fabric-like and plastic properties found to be highly suitable for use as topsheet in disposable absorbent articles such as topsheet 22 14 and 15. The prior art structure 40 is generally in accordance with U.S. Patent No. 4,342,314. The fluid-permeable plastic structure 40 exhibits a plurality of apertures (apertures, e.g., 41) that are formed by a multiplicity of each other. intersecting, cross-like, fiber-like elements (eg, elements 42, 43, 44, 45, and 46) interconnected in a first or wearer contacting surface 50 of the structure. Each fiber-like element comprises a base portion (e.g., a base portion 51) disposed in a plane 52, and each base portion has a sidewall portion (e.g., a sidewall portion 53) attached to each edge thereof. Preferably, the sidewall portions extend generally in the direction of the second surface 55 of the structure, with the intersecting sidewall portions of the fiber-like elements interconnected between the first and second surfaces of the structure and terminating substantially parallel to each other in the plane 56 of the second surface 55.

The term "fiber-like" as used herein to describe the appearance of plastic structures generally refers to any pattern of fine scale extrusions or apertures, random or random, reticulated or unreticulated, which can provide an overall look and feel of woven or nonwoven fibrous structures viewed by the human eye. In describing the elements used to form the structure, the term "fiber-like" is used herein to describe the appearance or shape of these elements. As used herein, the term " macroscopically stretched " when describing bulky plastic structures, tapes and films, refers to structures, tapes and films that have been treated to conform to the surface of a three-dimensional forming structure so that both surfaces exhibit a three-dimensional pattern of this forming structures that are easily visible to the normal, naked eye when the perpendicular distance between the eye of the observer and the plane of the structure is about 30.5 cm.

The term "macroscopic" generally refers to features or features that are easily visible to the normal, naked eye when the perpendicular distance between the eye of the observer and the plane of the structure is about 30.5 cm. The term "microscopic" refers to features or features that are not readily visible to the normal, naked eye when the perpendicular distance between the eye of the observer and the plane of the structure is about 30.5 cm.

These macroscopically expanded structures, tapes, and foils conform to the surface of said molding structures, which is typically accomplished by extrusion or embossing (i.e., when the molding structure exhibits a pattern comprising first protrusions outward) or the opposite process (i.e., when the molding structure exhibits a pattern containing mainly capillary nets inward), or by extruding the resin melt directly onto the surface forming structures of both types. By contrast, the term " flaming " is used herein to describe plastic structures, tapes, and films, referring to the general state of a given structure, tape or film when viewed with the naked eye on a macroscopic scale.

In a particularly preferred embodiment, the side wall members 53 interconnected terminate substantially parallel to one another in the plane 56 of the second surface 55 and form holes 49

In the second surface 55 of the structure. The capillary network 59 formed by the interconnected sidewall portions allows free transfer of fluid from the first or wearer contacting surface 50 of the structure directly to the second surface 55 of the structure, without lateral fluid transfer between adjacent capillary networks.

Each of the fiber-like elements along its length has a substantially uniform U-shaped cross-section. In the case of a primary fiber-like element, its cross-section comprises a base portion disposed in the wearer plane and sidewall portion attached to each edge of the base portion extending generally in the absorbent direction. the inserts of the contact surface of the structure. The portions of the side walls that intersect with each other are interconnected between the surface of the contacting wearer and the surface of the structure contacting the absorbent pad, thereby forming a capillary network interconnecting opposing surfaces of the structure.

One of the drawbacks associated with the use of the plastic topsheets is that, despite their superficial fluid management characteristics, some users are very hesitant to locate the topsheet, which they easily perceive as a plastic consequence of its glossy (or glassy) appearance, in contact with their skin. In order to reduce this vitreous appearance on the visible surface of the structure, i.e., that part of the structure seen at the top, it has been found that incorporation of a microscopic pattern of surface aberrations (hereinafter "aberrations") that is not recognizable when perpendicular between the eyes of the observer and the plane of the structure about 30.5 cm. U.S. Pat.

No. 463,045 defines the relevant measures to be met for a certain three-dimensional stretched structure to have a substantially non-glazed (non-glazed) visible surface.

In a particularly preferred embodiment, the base portion 51 comprises a microscopic pattern of surface aberrations 58, generally in accordance with the aforementioned US Patent No. 4,463,045. This microscopic pattern of surface aberrations 58 provides a substantially non-gloss visible surface when random light beams hit the structure.

The topsheet of the type generally described in the aforementioned patent, having surface aberrations of US 4,463,045, exhibits a fabric-like appearance and tactile sensation, as well as a non-gloss visible surface. In addition, it is highly effective in promoting rapid fluid transfer from the first wearer contacting surface to the second or absorbent contacting pad. The topsheets of the latter type enjoy great commercial success on sanitary napkins due to their clean and dry appearance in use, as opposed to traditional, nonwoven fibrous topsheets.

The prior art structure 40, when used as the topsheet of an absorbent article, is typically treated with a surfactant to render the topsheet hydrophilic. The exposed surfaces of the base 51 and side wall panels 53 are generally treated with a surfactant to become substantially hydrophilic, thereby reducing the likelihood that body fluids will flow from the upper layer rather than being absorbed and absorbed by the absorbent core through the upper layer. . Suitable methods of administering surfactants are described in U.S. Pat

009 563, both issued to Osbom.

Despite the effective functioning of the prior art surfactant-treated fluid-permeable web 40 in the topsheet applications of disposable absorbent articles such as sanitary napkins, there may be some drawbacks associated with the topsheets of a similar assembly. For example, treating the entire exposed surface of the upper layer with a surfactant creates a very wettable surface which, when placed on the wearer's skin, may cause it to adhere to the wearer's skin. This, in turn, may create feelings of heat, sweat and / or bonding of the wearer, which may be perceived as undesirable by some users.

Moreover, although the capillary structures of the previous species are effective in fluid transport, their efficacy is limited so that these capillary structures can only move fluid once they reach the interior of the capillary. Fluid that moisturizes and stays on the wearer's contacting surface,

-5US 288371 B6 contributes to a 'wet' tactile feeling or impression and, to the extent that the fluid may be colored or opaque, also contributes to a 'stained' visual impression. The surface textures (treatments) naturally formed in the material, or given to it during molding, further increase the likelihood that residual fluid will be attached or retained in the wearer contacting surface rather to enter the capillary structures for transfer away from the surface. Thus, surface topography contributes to the desirable visual and tactile sensation when dry, may also tend to retain residual fluid on the exposed surface and also be less desirable in user conditions.

Giant. 2 is an enlarged, partially segmented, perspective representation of an embodiment of the fluid-permeable, three-dimensional, fabric-like structure of the formed film of the present invention. The geometric configuration of the fluid permeable structure 80 is generally similar to the prior art structure 40 of Figure 1 and generally in accordance with U.S. Pat. No. 4,342,314 to Radela et al. Other suitable formed films are described in U.S. Patent 3,929,135 issued Thompson Day 30 December 1975; No. 4,324,246, issued to Mullane et al. on April 13, 1982; and 5,006,394, issued to Baird on April 9, 1991.

The structure 80 is preferably formed of a thermoplastic film. Examples of suitable materials for use as structure 80 include, but are not limited to, polyolefins such as polyethylenes including linear low density polyethylene (weight), low density polyethylene, ultra low density polyethylene, high density polyethylene, and polypropylene; metallocene catalyst based polymers; nylon (polyamide); cellulose esters; poles (methyl methacrylate); polystyrene; poly (vinyl chloride); polyester; polyurethane; compatible polymers; compatible copolymers; biodegradable polymers; and mixtures, laminates and / or combinations thereof. Films made from these materials can be plasticized using suitable additives known in the art. Other additives may be added to achieve the desired physical characteristics. The fluid-permeable plastic structure 80 exhibits a plurality of fluid openings or passages (eg, apertures 71) that are formed by a multiplicity of intersecting, fiber-like elements (eg, elements 91, 92, 93, 94, and 95) interconnected in the first or wearer. contacting surface 90 of the structure. Each fiber-like element comprises a base part (for example, a base part 81) located in the plane 102 and each base part has a side wall part (for example, a side wall part 83) attached to each edge thereof. The sidewall panels 83 or intermediate panels extend generally in the direction of the second surface 85 of the structure. The intersecting sidewall portions of the fiber-like elements are interconnected between the first and second surfaces of the structure and terminate substantially parallel to each other in the plane 106 of the second surface 85. The term "fluid passage" is intended to encompass enclosed or at least partially enclosed structures or channels. that can carry fluids. Thus, the term fluid passage is intended to include the terms 'aperture', 'channel', 'capillary', as well as other similar terms.

In a particularly preferred embodiment, the interconnected side wall portions 83 or intermediate portions terminate substantially parallel to one another in the plane 106 of the second surface 85 to form apertures 89 in the second surface 85 of the structure. The capillary nets 99 formed by the interconnected sidewall portions 83 or intermediate portions allow free transfer of fluid from the first or wearer contacting surface 90 of the structure directly to the second surface 85 of the structure, without lateral fluid transfer between adjacent capillary networks.

In accordance with the present invention, the first or wearer contacting surface 90 of the structure 80 is relatively non-wettable, as compared to the relatively wettable sidewall panels 83 or intermediate panels. A useful wettability parameter is the contact angle formed by a drop of fluid (gas-liquid interface) with the other surface (gas-solid body interface). Typically, a drop of fluid 110, located on the rigid surface 112, forms an angle of contact A with the rigid surface, as seen in FIG. 3. When the wettability of the rigid body decreases with fluid, the angle of contact A increases. The fluid-solid contact angle can be determined by techniques known in the art, such as those described in more detail in Physical Surface Chemistry, Second Edition, by Arthur W. Adamson (1967), F. E. Bartell and H.H. Zuidama, Journal of the American Chemical Association, 58,

-6GB 288371 B6

1449 (1936), et al. J. Bikerman and Ind. Eng. Chem. Anal. Ed '13, 443 (1941). More recent publications in this field include Chenga et al., Colloids and Surfaces. 43: 151-167 (1990), and Rotenberg et al., Joumal of Colloid and Interface Science. 93 (11: 169-183 (1983)) As used herein, the term "hydrophilic" refers to surfaces that are wettable with aqueous fluids (eg, aqueous body fluids) deposited thereon. Hydrophilicity and wettability are typically defined in terms of angle. The contact and surface tension of the fluids and solid surfaces involved is similarly discussed by the American Chemical Society's publication Angle of Contact, Wettability and Adhesion, edited by Robert F. Gould (Copyright 1964), which is considered wetted by some fluid (hydrophilic), Accordingly, the surface is considered to be hydrophilic when the fluid does not tend to spontaneously disperse over the surface. The respective contact angle depends on surface inhomogeneities (chemical and physical, roughness example), contamination , chemical / physical treatment or composition (composition) solid The surface energy of the rigid body also affects the angle of contact. As its surface energy decreases, the contact angle increases, and when its surface energy increases, the contact angle decreases.

The energy required to separate a fluid from a rigid surface (eg a foil or fiber) is expressed by the following equation (1):

(1) W = G (1 + cos A) in which:

W - is the adhesion work measured in J / m2,

G - is the surface tension of the fluid measured in N / cm, and

A - is the angle of contact of the liquid-solid surface measured in degrees.

For a given fluid, the adhesion work increases with the cosine of the liquid-surface contact angle (reaching the maximum where the contact angle A is zero).

Adhesion work is a useful tool in understanding and quantifying the surface energy characteristics of a given surface. Another useful method that could be used to characterize the surface energy features of a given surface is a parameter called "critical surface tension" as discussed by H. W. Fox, E. F. Hare and W. A. Zisman vJ. Colloid Sci., 8, 194 (1953), and W. A. Zisman in Advan. Chem. Series Nr. 43, Chapter 1, American Chemical Society (1964), both incorporated herein by reference.

Table 1 below shows the inverse relationship between contact angle and wash adhesion for a particular fluid (eg, water) whose surface tension is 750 N / cm.

Table 1

A (degrees) cos A, 1 + cos A W (m / m ² ) 0 1 2 1.5 30 0.87 1.87 1.4 60 0.5 1.50 1.13 ”90 0 1.00 0.75 120 -0.5 0.5 0.38 150 -0.87 0.13 0.1 180 -1 0 0

As shown in Table 1, when the work of adhesion of a particular surface decreases (exhibits less surface energy of a particular surface), the angle of contact of the fluid on the surface increases and thus the fluid tends to "roll" and occupy a smaller surface area of contact. The opposite is true when the surface energy of a given fluid decreases. Fluid work therefore affects interfacial fluid phenomena on a given rigid surface.

More importantly, in the context of the present invention, surface energy or discontinuity gradients have been found to be useful in promoting fluid transfer. Giant. 4 illustrates a fluid drop 110 that is disposed on a rigid surface having two regions 113 and 115 having different surface energies (for the purposes of imaging indicated by different dashes). In the situation shown in Figure 4, the region 113 exhibits a comparatively lower surface energy than the region 115 and hence reduced wettability for the fluid drop than the region 115. Accordingly, the drop 110 forms an angle of contact A (b) at the edge of the drop contact region 113. which is greater than the contact angle A (a) formed at the edge of the droplet contact region 115. It should be noted that although for the sake of graphical clarity the points "a" and "b" lie in one plane, the distance "dx" between these points a and b it may not be linear, instead of representing the extent of contact of the drop / surface regardless of the shape of the surface. Thus, drop 110 is subjected to an imbalance of surface energy and hence external force due to differences in relative surface energies (i.e., surface energy gradient or discontinuity) between regions 113 and 115, which may be represented by the following equation (2):

(2) dF = G [cosA (a) -cos A (b)] dx in which:

dF - numbers force per drop of fluid, dx - distance between reference points "a" "b",

G - is as defined in the previous, a

A (a) and A (b) - are the angles of contact at "a" and "b" respectively.

Solving equation (1) for cos A (a) and cos A (b) and substituting it for equation (2) gives equation (3):

(3) dF = G [W (a) / G-1) - (W (b) / G-1)]

Then equation (3) can be simplified to equation 4): _ (4) dF = (W (a) -W (b)) dx

The significance of the difference in surface energy between the two surfaces is clearly underlined in equation (4), as it is a directly proportional effect that changes in the magnitude of the difference in the work that adhesion will have to the magnitude of a given force.

A more detailed discussion of the physical nature of surface energy and capillarity effects can be found in Textile Science and Technology, Volume 7, Absorbence, edited by Portnoy K. Chatterjee (1985), and in Kapilarita, Theory and Practice, Ind. Eng. Chem. 61.10 (1969) by A. M. Schwartz.

Accordingly, the force transmitted by the drop will cause movement in the direction of higher surface energy. For simplicity and graphical clarity, the surface energy or discontinuity gradient in Figure 4 was highlighted as a single, sharp discontinuity or boundary between well defined regions of constant but varying surface energy. The surface energy gradients may also exist as a continuous gradient or stepped gradient, with the force applied to each particular drop (or portions of the drop) determined by the surface energy in each particular drop contact area. The term "gradient" is used when applied to differences in surface energy or adhesion work, is

It is intended to describe a change in surface energy or adhesion work occurring over some measurable distance. The term "discontinuity" is intended to refer to the type of "gradient" or transition in which the change in surface energy occurs over substantially zero distance. According to usage, all "discontinuities" fall under the definition of "gradient".

The terms "capillary" and "capillarity" refer to passages, apertures, pores, or gaps within a structure that are capable of transporting fluid in accordance with the relevant capillarity principles, generally represented by the Laplace equation (5):

(5) p = 2G (cos A) / R in which:

p - capillary pressure,

R - inner capillary radius (capillary radius), a

G and A - are as defined above.

As reported in the Intersection of Emery I. Valko, which is in Chapter III of Chem. Aftertreat Text. (1971), pp. 83-113, which is hereby incorporated by reference, for A = 90 degrees, cos A is zero and there is no capillary pressure. For A> 90 degrees cos A is negative and this capillary pressure faces the fluid inlet to the capillary. Thus, capillary walls must be hydrophilic in nature (>> 90 degrees) in order for capillary events to occur. Also, R must be sufficiently small that p has a significant value because, as R increases (larger aperture / capillary structure), capillary pressure decreases.

Perhaps as important as the presence of surface energy gradients is the particular orientation or location of the gradients themselves, with respect to the orientation and location of the capillaries or fluid passages themselves. More specifically, the surface energy or discontinuity gradients are positioned relative to the capillaries so that the fluids cannot remain on the first or top surface without contacting at least one surface energy or discontinuity gradient, and are thus acted upon by the driving force accompanying the gradient. Fluid displaced into or otherwise present in the capillary inlet will preferably contact at least one Z-direction gradient or discontinuity present in the capillary itself near the inlet to the capillary, and thus pass the Z-directional driving force to drive the fluid into the capillary where the capillary forces take up the fluid from the first surface. In a preferred configuration, the capillaries preferably exhibit a low surface energy inlet length and an otherwise higher surface energy of the capillary wall or surface such that the surface energy or discontinuity gradient is of a comparatively small but finite distance below the first surface. At such a location, the discontinuity or gradient is positioned such that the fluid in contact with the first surface at the periphery of the capillary or across the open end of the capillary will have a lower surface or meniscus that extends downward to the open end of the capillary to contact the discontinuity.

By further explaining this principle, Fig. 5 shows a fluid drop 110 that is placed over a generic capillary or fluid passage. This representation is considered generic enough to present the concept expressed herein, without being limited to a particular material of structure, design or assembly. Analogous to FIG. 4, the capillary is formed to represent surfaces 113 and 115 having different surface energies (for the purposes of imaging indicated by different dashes). As in Fig. 4, the surface energy of the surface 113 is at a predetermined level that is comparatively low compared to that of the surface 115, so that the surface 113 is considered hydrophobic. Accordingly, the edges of the droplet in contact with the surface 113 exhibit a relatively greater contact angle A, so that the edges of the droplet sharply deviate from the interface with the surface 113. On the other hand, the surface 115 has a comparatively higher surface energy compared to the surface 113.

-9EN 288371 B6

In the situation shown in Fig. 5, the drop 110 is shown to be positioned over and extending partially into the inlet opening of the capillary under a condition where the surface tension and gravitational forces are roughly equilibrium. The lower portion of the drop, which is within the capillary, forms a meniscus 117 at its periphery in contact with the capillary wall in region 113 having hydrophobic surface energy characteristics. The surface energy, discontinuity, or transition between surfaces 113 and 115 graphs are partially designed to contact the lower portion of the droplet near the meniscus edge 117. Droplet orientation and depth of the meniscus of the droplet are determined by such factors as fluid viscosity, fluid surface tension, capillary size and shape , and the surface energy of the top surface and the capillary inlet.

Once the droplet is placed over the capillary inlet and its lower edge contacts the Z-direction surface energy gradient, discontinuity or transition between surfaces 113 and 115, the meniscus 117 which has a convex shape turns into a concave-shaped meniscus such as meniscus 119 dashed line. When the meniscus changes into a concave form such as meniscus 119, the fluid moistens the capillary wall near the upper region of the hydrophilic surface 115 and the fluid passes through an external force due to the surface energy difference described above by equation (3). The combined surface energy and capillary pressure forces thus cooperate to draw the fluid into the capillary to capillaryly transfer fluid from the first surface. When the fluid drop moves down into the capillary, the comparatively low nature of the surface energy of the surface 113 in the upper region of the capillary minimizes fluid attraction to the top surface and minimizes tensile forces per drop, reducing the occurrence of fluid attachment or retention on or near the top surface.

Water is used throughout as a reference fluid only as an example and is not to be construed as limiting. The physical properties of water are well established and water is readily available and has generally homogeneous properties wherever it is obtained. The concept of working with water-related adhesion can easily be applied to other fluids such as blood, menses and urine, taking into account the characteristics of the particular surface tension of the desired fluid.

Referring to Fig. 2, while the first or wearer contacting surface 90 of the structure 80 has relatively low surface energy and relatively little adhesion work for a given fluid (e.g., water or body fluids as menses), sidewall panels 83, or intermediate structural members 80 preferably have a relatively high surface energy and a relatively high adhesion work for the fluid. Because the side walls 83 of the structure 80 have a relatively high surface energy compared to the first surface 90, the side walls 83 are more wettable than the first surface 90. The second surface 85 of the structure 80 preferably has a higher surface energy and more fluid adhesion work than the first surface 90 The surface energy and the adhesion work of the second surface 85 may be the same as the side walls 83. In a preferred embodiment, the surface energy and the adhesion work with respect to the fluid of the second surface 85 is relatively higher than that of the side wall 83.

By having a surface energy gradient structure formed by structures producing relatively low surface energy of the adjacent portion of the structure that will be positioned adjacent to the skin of the wearer (i.e., the first surface 90) and a relatively high surface energy portion located outside the skin contact of the wearer (side wall parts 83 or intermediate parts), the structure 80 is able to move a drop of fluid from a portion of the structure having relatively lower surface energy to a portion of the structure having a relatively higher surface energy. The movement of the fluid drop is induced by the difference in contact angle between the lower surface energy portion and the higher surface energy portion, resulting in an imbalance in the surface tension force acting on the liquid-solid contact plane. It is believed that this resulting surface energy gradient enhances the fluid handling properties of the structure 80 of the present invention and makes this structure particularly suitable for use on the topsheet of the absorbent article, for example, the topsheet 22 on the absorbent article 20 14.

In addition to improved fluid management properties, by designing the structure so that a portion of relatively lower surface energy can be placed in contact with the wearer's skin, adhesion between the skin and the structure is reduced by reducing the capillary force generated by occlusive body fluids positioned between the first surface of the structure and the skin of the wearer.

-10GB 288371 B6

By providing a structure with reduced adhesion between the wearer's skin and the structure, the perception or feel of tack associated with adhesion to the topsheet of the plastic structure is also reduced. The rewet potential is also reduced in that the topsheet has a surface energy gradient as described above. When the forces applied tend to push the collected fluid to rewet or squeeze out of the pad (e.g., extruding from the absorbent core toward the first surface of the topsheet), the first surface of the topsheet, which has a relatively low surface energy to repel the fluid, as this attempts to find a path from the insert through the openings in the topsheet.

In addition, the fluid is able to enter the topsheet more rapidly, due to the driving forces of the surface energy gradients of the topsheet. The fluid is moved in a direction 7 towards the second surface of the topsheet through a surface energy gradient from the first surface to the sidewall portions of the topsheet with a relatively higher surface energy toward the absorbent core.

With respect to the surface energy gradient of the present invention, it is important to remember that the upper and lower boundaries of each such gradient are relative to each other, i.e., the regions of the structure whose interface defines the surface energy gradient need not be on different sides of the hydrophobic / hydrophilic spectrum. The gradient may be formed by two surfaces with different degrees of hydrophobicity or different degrees of hydrophilicity and need not necessarily be formed with respect to any hydrophobic surface and hydrophilic surface. Notwithstanding the foregoing, it is presently preferred that the top surface of the structure has a comparatively low surface energy, i.e., is generally hydrophobic, to maximize the driving force imparted to the incoming fluid and to minimize the overall wettability of the wearer of the contacting surface.

Although many prior art structures have attempted to utilize different surface coatings (coatings) to impart greater hydrophobicity and / or reduced coefficient of friction to the overall top surface of the structure, these coatings typically significantly reduced, unless they directly eliminated topographical surface features in the uncoated structure. As mentioned above, these surface features are an important physical feature with respect to visual and tactile perception. In addition, these packages typically have a smooth, glossy final appearance, emphasizing the sticky, sweating and plastic feel of these structures.

Without wishing to be bound by theory, it should be noted that surface topology plays a major role not only in reducing the visual and tactile sensations normally associated with these structures, but also in handling and / or transporting and retaining body fluids. Accordingly, the fluid permeable structures of the present invention are preferably constructed to maintain the topography of the physical surface by the action of the formed film, i.e., in which the surface features survive the gradient generating process.

Giant. 6 is an enlarged partial view more clearly emphasizing the orientation of the regions 98 on the first surface 90 and in the capillaries in the formed film of FIG. 2. It should be noted with reference to FIG. clarity exaggerated in thickness resolution. The randomness and irregularity of these settlements or treatments exceeds the limitations of the graphic accentuation and hence these representations are intended to be illustrative and non-limiting. Accordingly, regions 98 highlighted in FIG. 6 are also preferably scattered by even smaller regions that are too small and random to be adequately represented in this representation. By reference, the surface texture in the form of microscopic aberrations (designated 58 in Fig. 1, not numbered but shown in Figures 2, 6 and 7) is (as defined by reference to Ahra et al.) At the microscopic level, and accordingly may therefore, the relative size, thickness and extent of the regions 98 should be assessed.

Thus, the surface energy gradients of the present invention exist in a unique relationship to the surface features and / or textures of the fluid permeable structure made in accordance therewith. As shown in more detail in FIG. 6, the surface energy gradients are preferably assembled by forming low surface energy regions 98 that interconnect with surrounding regions of the structure having

-11GB 288371 B6 comparatively higher surface energy. Thus, each region 98 generates a surface energy gradient at its boundaries. Accordingly, the greater the number of regions 98, the greater the number of individual surface energy gradients. The regions 98 are preferably discontinuous (i.e., not entirely surrounding the structure) and spaced apart, leaving intervening regions with higher surface energy.

Also note in FIG. 6 the marking of the surface energy treatment thickness t used to generate the regions 98 and the depth Z to which each particular region 98 extends below the first surface 90 of the structure. The thickness t is preferably small in relation to the depth Z or extension of the regions 98 in order to minimize the impact of the generation of regions on the topography of the layer. In the case where the regions 98 are generated by a wrap, the thickness t is the thickness of the wrap. Where the regions are formed by changing the chemical composition of the structure material, the thickness t will be less than or nearly equal to the caliber of the film or thickness.

In each gradient, the droplet contacting both surfaces is subjected to a driving force which imparts some degree of fluid movement and reduces the likelihood that the fluid will stand or become trapped, particularly on the topography of the surface. Although the regions 98 could be applied in a predetermined pattern, the regions 98 are preferably randomly oriented on the surfaces of the structure, with a randomness increasing the likelihood that surface energy gradients will be appropriately positioned to cover all particular drops or quantity of fluid. Randomness is desirable not only across the first surface of the structure but also within the fluid passages themselves. Accordingly, any particular capillary or passage may exhibit multiple surface energy gradients defined by regions 98 that may also be located at different locations in the Z direction from the first surface. Also, specific fluid passages may have more or less regions 98 than other fluid passages, and regions 98 may also be positioned to rest entirely within the fluid passages (i.e., fully positioned between the first and second surfaces).

The regions 98 are also preferably discontinuous in nature with respect to the directionality of the structure. In FIG. 6 it is particularly evident that the surface treatment is preferably discontinuous with respect to the surface regions, the structures between successive capillaries. The discontinuity of treatment of the hydrophobic surface applied to a less hydrophobic (or more hydrophilic) substrate such as the surface of the structure results in small-scale surface energy gradients in the plane of the surface. These gradients need to be distinguished from large-scale X-Y grades of zonal nature by their relatively small size versus the average surface droplet size, topography, or surface energy gradients that are smaller in size than the average fluid droplet size on the surface in question. The average droplet size has readily determinable characteristics that can be obtained by empirical observations of given fluids and surfaces. As a reference, in the structure as in Fig. 2, the average droplet sizes for the artificial menstrual fluid (defined below) are typically large enough to cover at least 2-3 individual capillaries upon initial contact (prior to acquisition, soaking).

Without wishing to be bound by theory, it should be noted that improvements in fluid flow characteristics are accomplished by reducing the residence time of the fluid on the top surface of the structure, as well as by moving the fluid from the top surface to the capillaries for capillary fluid transfer. Thus, it is believed that it is desirable for the initial fluid contacting the surface of the structure to facilitate fluid movement on a small scale (as opposed to greater lateral movements across the surface of the structure), towards the nearest available capillary and then rapidly downwardly into the underlying structure. The surface energy gradients of the present invention provide the driving force of the desired Z direction as well as the force X-Y to impart the desirable fluid movement on a small scale.

The plurality of small-scale surface energy gradients exhibited by these structures is beneficial from the fluid movement perspective. Small scale gradients assist in lateral or X-Y movement of fluid droplets formed on the surface of the structure that could otherwise be arranged to be over the areas between the capillaries or surface concavity present on the surface of the top structure where fluid might otherwise be retained or at least

-12GB 288371 B6 delayed on its way to the nearest available capillary. Accordingly, the small-scale surface energy gradients on the surface of the capillary network structure preferably have average gaps that are smaller than the average gaps between the capillaries, so that they otherwise interrupt the areas with constant surface energy between the capillaries.

In addition, regions 98 that are smaller in surface area than a typical droplet size, stream, or body fluid incident thereon, subject droplets, streams, or streams of body fluid to destabilizing forces due to the inevitable fluid bridging of some surface energy gradient or discontinuity.

While the surface energy gradient described herein could advantageously be applied to non-capillary structures, including the surface of such structures as two-dimensional (flame) films of the present invention, it is preferred to use both small-scale XY surface energy gradients and low-Z surface direction energy gradients. scaling of the type described herein to achieve maximum disturbance of fluid and equilibrium of the droplet, thereby minimizing droplet residence time and attachment or / or residue on top regions of the structure. Accordingly, the presence of the regions 98 may be limited to the first surface of the structure and thus provide X-Y functionality, or limited to the interior of the fluid passages, but is preferably utilized to the greatest advantage both on the first surface and within the fluid passages.

In the capillary structure assemblies of the present invention, the surface energy gradients provide a synergistic effect in conjunction with the nature of the capillaries of the structure to provide improved fluid transfer and handling characteristics. Fluid on the first surface of the structure faces two different and complementary driving forces as it travels from the first surface and towards the second or opposite surface of the structure and typically further inwardly of the absorbent article. Similarly, the two forces combine to counter the movement of the fluid towards the first surface of the structure, thereby reducing the occurrence of rewet and increasing the surface dryness of the structure. By way of an exemplary display of the synergism of the present invention versus the junction or superposition of the capillary and surface energy effects, the capillary structures of the present invention have been found to exhibit a unique combination of properties found to be important from a consumer perspective. More specifically, the capillary structures of the present invention have been found to exhibit good acquisition, dryness and masking characteristics, which are further defined herein.

In general, uptake is a reflection of the degree to which fluid transport through a given structure does not interfere with fluid throughput. Increased acquisition / time doses reflect interference or impedance of fluid passage, as well as the real effect of fluid driving forces such as capillaries and surface energy gradients. The dryness is a reflection of the degree to which fluid transport through the structure resists fluid transport in the reverse direction, essentially the degree to which the structure operates as a one-way valve for fluid flow in the preferred direction. The masking reflects the cleanliness of the surface after passing through the fluid, further defined as the degree of remaining color (by stained fluid), as well as the size or extent of the colored region (region).

Typically, when the surface energy of a given capillary structure decreases uniformly, masking and dryness at the surface improves, but at the expense of limiting reception characteristics. Accordingly, the reception improvements realized by uniformly increasing the surface energy of a given capillary structure are typically offset by reduced masking and dryness characteristics. By using the surface energy gradient principles of the present invention, in which the surface energy of the top surface is reduced while the surface energy of the bottom surface remains higher, and in particular by preferential orientation and location of the gradients themselves, increased uptake, dryness and / or masking characteristics can be achieved without sacrificing the remaining parameters. Suitable analytical or test methods for determining the performance of a given structure with respect to these attributes are described in more detail in the ANALYTICAL METHODS section below. A number of physical parameters should be considered when designing the structure of the invention, more particularly with respect to determining the appropriate size and location of surface energy gradients for proper fluid handling. These factors include the magnitude of the surface difference

Energy (which depends on the materials used), material migrability, material biocompatibility, porosity or capillary size, overall diameter and geometry, surface topography, fluid viscosity and surface tension, and the presence or absence of other structures on either side of the structure.

Preferably, the regions 98 of the web 80 have an adhesion work with respect to water up to about 15 J / m 2, more preferably up to about 7.5 J / m 2. Preferably, the rest of the structure surrounding the regions 98 has an adhesion work with respect to water of up to about 15 J / m 2, more preferably in the range of about 2.5 J / m 2 to about 15 J / m 2, and most preferably in the range of about 5 J / m 2 to about 15 J / m2. Preferably, the difference in water adhesion work between the first regions 98 and the rest of the structure is in the range of about 0.5 J / m 2 to about 14.5 J / m 2, more preferably in the range of about 2.5 J / m 2 to about 14 J / m 2. 5 J / m 2, and most preferably ranging from about 5.0 J / m 2 to about 14.5 J / m 2.

In order to produce the structure 80 shown in FIG. 2 having a surface energy gradient according to the present invention, the polyethylene layer (film) is suppressed into a drum where it is vacuum formed into an apertured formed film and then, if desired, subjected to corona discharge treatment, in accordance with U.S. Patents 4,351,784 issued to Thomas et al. on September 28, 1982; No. 4,456,570, issued to Thomas et al. on Jun. 26, 1984; and 4,535,020 issued to Thomas et al. on August 13, 1985. The polyethylene may, if desired, have a resin-treated surfactant, or typically applied. A relatively low surface energy surface treatment is then applied to the first surface of the aperture formed film to form the regions 98 and preferably cured. A suitable surface treatment is a silicone release liner to which an enhancer is added in a weight ratio of 100 parts to 10 parts, respectively. Yet another suitable surface treatment is a UV-cured silicone coating containing a mixture of two silicones in a weight ratio of 100 parts to 2.5 parts. When this silicone mixture is applied to the formed film as shown in Figures 2 and 6, application levels of the coating of from about 0.5 to about 8.0 grams of silicone per square meter of the surface area of the structure have worked satisfactorily, although for certain applications other levels of packaging, depending on the nature of the material of the structure and surface, fluid characteristics, etc. The surface energy of the silicone release liner on the first surface of the aperture molded film is less than the surface energy of the polyethylene intermediate parts that may have been corona treated and / or treated with some surfactant.

Other suitable treatment materials include, but are not limited to, fluorinated materials such as fluoropolymers (eg, polytetrafluoroethylene, TPFE), and chlorofluoropolymers. Other materials that may be suitable for providing regions with reduced surface energy include Petrolatum, latexes, paraffins and the like, although silicone materials are currently preferred for use in fluid-permeable structures in the context of absorbent articles because of their biocompatible properties. The term "biocompatible" refers to materials having a low level of specific adsorption for, or in other words low affinity for, biospecies or biological materials such as glucoproteins, platelets and the like. As such, these materials tend to resist, on useful conditions, the deposition of biological material on a larger scale than other materials. This property allows them to better maintain their surface energy properties needed for the post-fluid control situation. In the absence of biocompatibility, deposition of such biological material tends to increase surface roughness or inhomogeneity, resulting in increased entrainment force or resistance to fluid movement. Consequently, the biocompatibility corresponds to a reduced entrainment (tensile) force or resistance to fluid movement, and thus faster fluid access to the surface energy gradient and capillary structure. Maintaining substantially the same surface energy also maintains the original surface energy difference for subsequent and sustained fluid storage.

However, biocompatibility is not synonymous with low surface energy. Some materials, such as polyurethane, exhibit biocompatibility to some degree, but also exhibit comparatively high surface energy. Some low surface energy materials that might be attractive for use here, such as polyethylene, lack biocompatibility. At the same time

Preferred materials such as silicone and fluorinated materials preferably exhibit both low surface energy and biocompatibility.

Suitable surfactants for hydrophilizing or increasing the surface energy of selected regions of the structure include, for example, ethoxylated esters, glucose amides, triblock copolymers of ethylene oxide and propylene oxide, and copolymers of silicone and ethylene glycol. These sulfactants may be incorporated into the polymer starting material (resin-incorporated reagent, or RIS) of the structure, in accordance with the aforementioned, published PCT application WO 93/09741, or alternatively applied to the surface of the structure by spraying, printing, or other by suitable methods as disclosed in U.S. Patent No. 4,950,264 issued to Osbom.

Alternatively, yet another approach to the generation of the surface energy gradient structures of the present invention comprises immersing a sidewall portion 83 of the corona and silicone treatment structure 80 in a wetting agent (e.g., an aqueous reagent solution) such that the sidewall portions 83 have a relatively higher surface energy. than the first surface 81 (regions 98) of the structures having koranic and silicone treatment.

Another preferred method of converting a polyethylene film tape, which may optionally have a surfactant admixed therein, into the perture formed film is by application of a high pressure fluid jet composed of water or the like, against one surface of the film, preferably at the same time. using a vacuum adjacent the opposite surface of the film. These methods are described in more detail in U.S. Pat. No. 4,609,518, issued to Curro et al .; No. 4,629,643 issued to Curro et al .; 4,637,819, issued to Quellette et al., 4,681,793, issued to Linman et al., 4,695,422, issued to Curro et al., 4,778,644, issued to Curro et al .; 4,839,216 issued to Curro et al .; No. 4,846,821 issued to Lyons et al. The aperture molded film may then, if desired, be subjected to corona discharge treatment. The silicone release liner can then be applied to the first surface of the apertured formed film to generate regions 98 and is then preferably cured. The intermediate and lower portions of the formed film aperture structure may be covered by immersion in a wetting agent such that the silicone-untreated intermediate and lower portions of the structure have a relatively higher surface energy than the first surface 81 (regions 98) of the structures having the koranic and silicone treatment. The surface energy of the silicone-treated regions 98 is then lower than that of the untreated portions of the structure.

Giant. 7 emphasizes yet another method of forming a formed film having a surface energy gradient according to the present invention using a multilayer film in the forming process as described above. The first film layer 103 forming the surface of the structure is formed from the first material, while the second film layer 101 forming the second surface of the structure is formed from the second material. Preferably, the second material exhibits greater ductility and higher surface energy than the first material, so that during the punching process the first film layer 103 breaks (the first) while the second film layer 101 extends to a greater extent and forms the lower portion of the structure. The first surface of the finished structure is thus composed of the first material, while the intermediate and lower portions of the finished structure are composed of a second material exposed after breaking the first material, with a boundary between the two materials located in the capillaries and slightly below the first surface of the structure as shown in FIG. Thus, the finished structure exhibits a surface energy gradient from the first surface to the second surface, defined by the interface between the edge of the first layer 103 (the "region" corresponding to those in Figure 6), without the additional steps of treating the first, intermediate and / or second surface with additives or shells. potahy). In Figure 7, note the irregularity of the edge of the first layer 103 that corresponds to the random distance of the surface energy gradient (defined by the edge of the region 103) from the first surface of the structure. The first and second layers described herein may be separated from one another by one or more intervening layers in a multilayer film (not shown), having 3 or more layers, which may optionally participate in the surface energy gradient of the film by having surface energy characteristics in between which has the (top) and (bottom) layer.

-15GB 288371 B6

Giant. 8 and 9 show a perspective view of another embodiment of the fluid transfer structures 200 of the invention. The fluid transfer structure 200 comprises a fluid permeable nonwoven structure 202, preferably comprised of polypropylene fibers 203. Other suitable fibers include natural fibers such as wood, cotton or rayon, or synthetic fibers such as polyester or polyethylene, bicomponent fibers, or combinations of natural and synthetic fibers. fibers, such as assorted paper, tissue paper, or paper-like fibrous materials. The nonwoven structure 202 preferably has a first or upper surface 205 and a second or lower surface 206. The first surface 205 is separated from the second surface 206 by the intermediate portion 207. The first surface 205 preferably has a plurality of regions 210 corresponding thereto corresponding to regions 98 shown in FIG. The regions 210 preferably exhibit comparatively low surface energy and preferably include treating the low surface energy surface as described above with respect to the embodiment of FIGS. 2 and 6. The plurality of apertures 215 preferably extend from the first surface 205 to the second surface 206 of the nonwoven. structures 202.

The regions 210 preferably have a relatively low surface energy and a relatively low adhesion work as compared to nonwoven fibers having a relatively high surface energy and a relatively high adhesion work. Accordingly, the treated nonwoven web 200 exhibits a plurality of surface energy gradients defined by the boundaries of the regions 210, i.e., the interface between the regions 210 and the surrounding fibrous surfaces.

Surface treatments for generating regions 210 may be applied to the first surface 205 of the nonwoven web 202 by techniques known in the art such as screen printing, gravure printing, spraying, dipping, etc. The nonwoven web 200 may be apertured by methods known in the art such as needling, hydroentangling, annular rolling (rolling between intermeshing corrugated rolls), longitudinal slitting and stretching, punching, etc.

In configurations in which a given structure has a defined aperture, the surface treatment of the regions 210 is preferably applied to the first surface of the nonwoven web upon completion of the aperture opener. The surface treatment of the regions 210 may alternatively be applied to the first surface of the nonwoven web prior to the aperture operation.

As shown in FIG. 9, the relationship of the regions 210 to surface topography (comprising individual fibers projecting upwardly from the top surface of the structure) is considered an important aspect of the present invention. Notice the discontinuous or discontinuous, distant nature of these regions with respect to the surface direction of the structure and the thickness direction of the structure, especially since the surface treatment as in Fig. 9 is actually a plurality of discrete portions, drops or globules with than by bridging or masking the fibers, which would cause the fibers to occlude between the poles. As discussed above, this discontinuity leads to the generation of a plurality of surface energy gradients of small scales, which is considered beneficial from the perspective of fluid movement.

Figure 9 also clearly illustrates the penetration of the surface treatment into and below the first surface 205 of the nonwoven web 202. While most regions 210 are concentrated near the first surface 205 itself, the treated regions extend downwardly through the fiber-fiber structure to achieve analogous penetration to that defined above with respect to the structure of the formed film. The regions 210 are preferably concentrated near the first surface 205 and reducing the frequency (increasing the gaps) with increased distance from the first surface such that regions with low surface energy and therefore more surface energy gradients are generated at or near the first surface 205 for greater fluid effect on the surface. or near the first surface. Thus, on average, the upper regions of the structure near the first surface will exhibit a lower average surface energy than the lower regions of the structure closer to the second surface.

Although the foregoing discussion has focused on a currently preferred aperture nonwoven structure having discrete apertures of comparable magnitude relative to the fiber gap, it is believed that

The principles of the present invention are applicable with the same effect to non-aperture nonwoven structures with sufficient effective porosity to permit desirable fluid passage characteristics. It is believed that this applicability is due to the non-occlusion of the inter-fibrous capillaries such that sufficient passageways remain open to transfer fluid to the underlying structure. In a structure having discrete apertures of comparable size in relation to the interstices between fibers, it is believed that it does not occlude them less important, but is still considered to be advantageous. Although the foregoing discussion has focused on a truly nonwoven substrate, it should be understood that the concept of the present invention could be applied in a similar manner to woven or hydride woven / nonwoven substrates. In doing so, knowing the degree of porosity present in a given interwoven structure must necessarily extrapolate the previous treaties on porosity and inter-fibrous capillary voids of nonwoven structures to interwoven structures. In addition, the term "fiber" as used herein is also intended to encompass a type of fibrous structure commonly referred to as "capillary channel fiber", ie, a fiber having a capillary channel formed therein. Suitable fibers of this kind are described in more detail in U.S. Patent Nos. 5,200,248, 5,242,644, and 5,356,405, all issued to Thompson on April 6, 1993, September 7, 1993, and October 18, 1994, respectively. The fibrous structures formed by these fibers may have not only inter-fibrous capillaries and gaps, but also intracellular capillary structures. Giant. 10 is an enlarged, partially segmented perspective view of an embodiment of the three-dimensional, fluid-permeable structure of the formed film of the present invention. The geometric configuration of the fluid permeable structure 310 is generally similar to that of Figure 2, but includes microapertures in accordance with commonly assigned U.S. Patent 4,629,643 to Curro and Linman.

Giant. 11 is an enlarged partial view of the structure of FIG. 10, highlighting in more detail the relationship of microapertures 325 to the overall assembly of the structure. Also shown in Figure 11 is a primarily undeformed surface of the structure (or surfaces) 328 between and around the surface aberration bases that culminate in microapertures 325 having thinned edges 326. The same figure also shows the presence of discrete, discontinuous spaced regions 390 that preferably exhibit comparable low surface energy compared to the intervening surfaces of the structure in a similar manner, shape and composition to those shown in Figure 6.

Giant. 12 is a cross-sectional view of one of the macroscopic structures of FIG. 11, highlighting the presence of regions 390 on the top surface of the structure. As shown in FIG. 12, based on certain circumstances, regions 390 may at least enter the interior of at least some microapertures 325 (as discussed in 391). This tends to further reduce the surface energy of the upper surface of the structure compared to the intermediate piece having unlocked microapertures. In addition, partially or completely overlapping the interior of the microapertures on the top of the formulated film with low surface energy regions further reduces the likelihood that fluid will adhere within the micro-hole, thereby increasing the dry feeling experienced by the wearer.

As shown in Figs. 11-12, the relationship of regions 390 to surface topography (containing microapertu 325) is considered an important aspect of the present invention. Note the discontinuous or discontinuous nature of these regions 390 with respect to the surface direction of the structure. As discussed above, this discontinuity leads to the generation of a plurality of small scale surface energy gradients at the interface between each region and the surrounding surface of the structure, which is considered beneficial from a fluid movement perspective.

FIG. 12 also emphasizes the penetration of regions 390 below the surface of the structure and down into the apertures analogously to the discussion of penetration above. Also shown in FIG. 12 is a different level or degrees of penetration of regions 390 into the macroapertures of the structure, with a microaperture 330 having a comparatively low penetration below the first surface of the structure and a macroaperture 340 having a greater degree of penetration. The regions 390 are preferably concentrated near the first surface and have a lower frequency (larger gaps) with increasing distance from the first surface so that more regions of low surface energy are generated, and therefore more surface energy gradients at or near the first surface to more effect on fluids. or near the first surface. Thus, on average, the upper regions of the structure near the first surface will have a lower average

-37GB 288371 B6 the lower regions closer to the other surface. More detailed details on the nature of the processes that can be used to produce microcaperture, macroscopic stretched and / or aperture molded films shown in Figures 10-12 are set forth in U.S. Patent 4,609,518, issued September 2, 1986 to Curro. et al. After the production of microcaperture molded films of the present invention, the surface film gradient properties of the present invention are granted to the molded film in the manner described above with respect to Figs. 2 and 6, and may be processed into absorbent articles such as those shown in Figs. Indeed, the surface energy gradient properties of the present invention are particularly useful in coping with the tendency of fluids to collect in and around the microstructures present in the formed films, as highlighted in Figures 10-12. This leads to structures having improved substance characteristics without sacrificing the apparent dry state of the consumer.

Although many of the foregoing have focused on unitary (one Z-directional structural element) fluid permeable structure with a single layer of material, it is understood that the principles of the present invention may equally apply to unitary (one Z-directional structural element) fluid permeable structure with multiple layers which have been joined into a composite structure. When such multilayer structures comprise multiple layers of materials of different physical characteristics (i.e., multiple layers of films, woven or nonwoven layers), these structures may also comprise a group of hybrid materials comprising layers of different physical material groups such as nonwoven / film composites, composites nonwoven / foil / nonwoven, etc. Such materials are believed to be the surface energy gradient principles of the present invention applicable to the surfaces of the resulting structure of the exposed structure exposed to the fluid in the same manner as described hereinabove for the respective material separately .

As an illustrative example of this aspect of the present invention, Figure 13 illustrates a nonwoven / film / nonwoven composite 510 in which the nonwoven surface faces the wearer as well as the incoming fluid. An exemplary composite of this kind is described in more detail in U.S. Patent No. 4,780,352, issued to Columbus on October 25, 1988. This composite structure in accordance with the present invention comprises an upper fibrous layer 530, an intermediate plastic film layer 540, and a lower fibrous layer 550 Accordingly, the principles of the surface energy gradient of the present invention embodied in regions 520 and further within and around the fibers of the top fibrous layer 530 are structurally and behaviorally similar in nature to the nonwoven structure shown and described above with respect to Figures 8 and 9. In addition, the plastic film layer 540 may function as a barrier to further penetration of the surface treatment used to generate the regions 520, thus ensuring their concentration near the top surface of the structure. Accordingly, when the top surface of the composite sheet is a fiber-backed film, the surface energy gradient principles of the present invention will be structurally and behaviorally similar in nature to that of the formed film shown and described above with respect to FIGS. 6, 7, 11 and 12. it is believed that the backsheets in the composite structure, while contributing to the overall structure characteristics, will not affect the fluid transport behavior in the initial fluid uptake to such an extent that they do not form the exposed surface of the incoming fluid.

Other suitable materials include polymeric foam materials comprising a hydrophilic flexible network of interconnected open spaces as a fluid transfer structure that can be imparted to the surface energy gradients of the present invention. Suitable foam materials of this kind are described in U.S. Patent Nos. 5,147,345, issued September 15, 1992 to Young et al., And 5,397,316, issued March 14, 1995 to LaVon et al.

In addition to the forming processes described above, the surface energy gradients of the present invention can be applied to film, nonwoven or composite structures that have been subjected to other mechanical processes such as creping, stretching / activation by rolling with corrugated rollers or otherwise. Such a mechanical procedure may be either an alternative to the procedures herein

288371 B6 described above or by addition to these processes, i.e., sequentially either before or after these processes.

Although the previous discussion focused on the simultaneous preferred approach of beginning with a predominantly hydrophilic structure and application of packaging, treatment or folding of the material to the generation of low surface energy regions and making the tops hydrophobic, it is understood that other approaches to generating surface energy gradients are also contemplated. , and are within the scope of this invention. These approaches will include applying a hydrophilic material (for example, a hydrophilic latex) to the lower portions of the initially hydrophobic structure to generate hydrophilic border regions in interfaces with the hydrophobic surfaces of the structure, forming a structure of two or more materials with different surface energy characteristics with surface energy gradients formed by boundaries between by appropriate materials, forming the structure of a material predominantly hydrophobic or predominantly hydrophilic and altering the surface chemical composition of its selected regions by mechanical, electromagnetic or chemical treatment, or treatment techniques known in the art, thereby generating selected surface energy gradients; surface energy, treating hydrophobic regions to be temporarily hydrophilic and to produce gradients when used surface energy, etc.

An exemplary absorbent article

The term "absorbent article" as used herein generally refers to devices that absorb and retain body exudates. More specifically, the term refers to devices that are positioned against or near the body of the wearer to absorb and contain the various exudates excreted by the body of the wearer. The term "absorbent article" is intended to include diapers, sanitary napkins, tampons, sanitary napkins, incontinence pads, etc., as well as wound dressings and sore spots. The term "disposable" as used herein refers to products which are not intended to be washed or otherwise recovered or reused as an absorbent article (ie, intended to be discarded after limited use and are preferably recycled, composted) or their disposal is otherwise, in a manner compatible with the protection of the environment). The term "unitary" or complex absorbent article refers to absorbent articles that are formed from separate parts joined together to form a coordinated entity so as not to require separate manipulative parts such as a separate holder and pad.

A preferred embodiment of the unitary absorbent article of the present invention is a sanitary napkin, sanitary napkin 20 as shown in Figure 14. The term "sanitary napkin" as used herein refers to an article worn by women adjacent the pubic region, generally outside the urogenital region and is intended to absorb and contain menstrual fluids and other vaginal discharge from the body of the wearer (e.g., blood, menses and urine). Interlabial devices that are located partially inside and partially outside the wearer's vestibule are also within the scope of this invention.

However, it should be understood that the present invention is also applicable to other sanitary napkins, sanitary napkins, or other absorbent articles such as diapers, incontinence pads and the like, as well as other structures designed to facilitate fluid transfer from the surface such as disposable towels, cosmetic handkerchiefs and the like.

It is to be understood that the overall size, shape and / or configuration of the absorbent article, if any, into which the fluid transfer structures of the present invention are incorporated or used together has no critical or functional relationship with the principles of the present invention. However, these parameters must be considered with the intended fluid and the intended functionality in determining the appropriate structure configurations and respective orientation of the surface energy gradients of the present invention.

-19GB 288371 B6

The sanitary napkin 20, as shown, has two surfaces, a first liquid-permeable surface 20a or a " body surface ", and a second liquid-impermeable surface 20b rotated. The sanitary napkin 20 is shown in Figure 14 as seen from its first surface 20a. The first surface 20a is intended to be worn adjacent the body of the wearer. The second surface 20b of the sanitary napkin 20 (FIG. 15) is on the opposite side and is intended to be positioned adjacent the wearer's undergarments when the sanitary napkin 20 is worn.

The sanitary napkin 20 has two central axes, a longitudinal central axis L and a basic transverse axis T. The term "longitudinal" as used herein refers to a line, axis, or direction in the plane of the sanitary napkin 20 that is generally on one axis s (e.g., approximately parallel to a vertical plane bisecting a standing wearer on the left and right body halves when the sanitary napkin 20 is worn. The terms "transverse" or "lateral" as used herein are interchangeable and refer to a line, axis or direction that lies within the plane of the sanitary napkin 20 that is generally perpendicular to the longitudinal direction. Giant. 14 also shows that the liner 20 has a perimeter 30 that is defined by the outer edges of the sanitary napkin 20 in which the longitudinal edges 31 (or "side edges") and the end edges 32 (or "ends") are present. Giant. 14 depicts a plan view of a sanitary napkin 20 of the present invention in a substantially flat state having cut-off portions for easier depiction of its assembly and with the portion of the napkin 20 facing or contacting the wearer facing the viewer. As shown in Figure 14, the sanitary napkin 20 preferably comprises a liquid pervious topsheet 22, a liquid impervious backsheet 23 bonded to the topsheet 22, and an absorbent core 24 positioned between the top 22 and backsheet 23, and a secondary topsheet or acquisition layer. 25 positioned between the topsheet 22 and the absorbent core 24.

The sanitary napkin 20 preferably includes optional side flaps 34 or "wings" that are folded around the crotch portion of the wearer's panties. The side flaps 34 may serve a number of purposes, including but not limited to helping to maintain a sanitary napkin attached to the panties while protecting the wearer's panties from contamination.

Giant. 15 is a cross-sectional view of the sanitary napkin 20 taken along section line 15-15 of FIG. 14. As seen in FIG. 15, the sanitary napkin 20 preferably includes adhesive fastening means 36 for attaching the sanitary napkin 20 to the wearer's undergarment. The removable releasable covers 37 cover the adhesive fastening means 36 and keep the adhesive from being applied to a surface other than the crotch portion of the undergarment prior to use.

The topsheet 22 has a first surface 22a and a second surface 22b disposed adjacent to, and preferably attached to, the first surface 25a of the fluid acquisition layer 25 to promote fluid transport from the top layer to the acquisition layer. The second surface 25b of the acquisition layer 25 is disposed adjacent to, and is preferably affixed to, the first surface 24a of the absorbent core or fluid storage layer 24 to promote transport of fluid from the acquisition layer to the absorbent core. The second surface 24b of the absorbent core 24 is disposed adjacent to, and is preferably attached to, the first surface 23a of the backsheet 23.

In addition to having the sanitary napkin 20 having a longitudinal and transverse direction, the sanitary napkin 20 also has a Z direction having a downward direction extending through the topsheet 22 and into any secured storage core or fluid layer 24. The goal is to provide a substantially continuous path between the topsheet 22 and the backsheet or layers of the absorbent article here such that the fluiodum is drawn in the Z direction from the topsheet of the article towards its final storage layer. The absorbent core 24 may be any absorbent means capable of absorbing or retaining fluids (e.g., menses and / or urine). As shown in Figures 14 and 15, the absorbent core 24 has a garment surface 24b, a body surface 24a, side edges and end edges. The absorbent core 24 is to be manufactured in a wide variety of sizes and shapes (eg, rectangular, oval, hourglass, dog bone, asymmetric, etc.) and a wide variety of liquid-absorbing materials commonly used in sanitary napkins and other absorbent articles.

Products such as pulverized wood pulp, which is commonly referred to as airfelt. Examples of other suitable absorbent materials include crepe cellulose wadding, meltblown polymers including coform, chemically stiffened, treated or crosslinked cellulose fibers, synthetic fibers such as curly polyester fibers, peat moss, tissue paper webs and tissue laminates, absorbent foams, absorbent sponges, superabsorbent polymers, absorbent gelling materials, or any equivalent materials, or combinations or mixtures thereof.

Also, the configuration and configuration of the absorbent core may be different (e.g., the absorbent core may have different palpability zones, i.e., profiled to be thicker in the center), hydrophilic gradients, superabsorbent gradients, or lower density or lower average acquisition zones. basis weight, or comprising one or more layers or structures). However, the total absorbent capacity of the absorbent core should be compatible with its intended device and use of the absorbent article. Further, the respective size and absorbent capacity of a given absorbent core may be varied to accommodate various uses such as incontinence pads, panty liners, regular sanitary napkins or sanitary napkins overnight.

Exemplary absorbent structures for use as the absorbent core of the present invention are described in U.S. Patent 4,950,264, issued to Osbom on Aug. 21, 1990; U.S. Patent 6,610,678 issued to Weisman et al. on September 9, 1986; U.S. Patent 4,834,735 issued to Alemany et al. on May 30, 1989; and European Patent Application No. 0 198 683, the Procter & Gambia Company, published October 22, 1986, by Duenka et al.

A preferred embodiment of the absorbent core 24 has a surface energy gradient similar to that of the topsheet 22. The body-facing surface 24a of the absorbent core and the portion of the absorbent core 24 immediately adjacent the body-facing surface preferably has a relatively low surface energy compared to the garment facing surface 24b. which has a relatively high surface energy. It is important to note that while there is a surface energy gradient within the absorbent core 24, the surface energy of the contacting or wearer facing surface 24a of the absorbent core is preferably greater than the surface energy of the garment facing surface 25b of the acquisition layer 25. This relationship is preferred the fluid could be drawn from the acquisition layer to the absorbent core. If the surface energy of the body-facing surface 24a of the absorbent core should be less than the garment-facing surface 25b of the acquisition layer, the fluid in the acquisition layer 25 would be repelled by the absorbent core, thereby rendering the absorbent core unnecessary.

The backsheet 23 and the topsheet 22 are disposed adjacent the garment facing surface and the body facing surface of the absorbent core 24 and are preferably joined thereto and joined together by attachment means (not shown), such as those well known in the art. For example, the backsheet 23 and / or the topsheet 22 may be attached to the absorbent core or to each other by a uniform, continuous layer of adhesive, its patterned layer, or any combination thereof into separate lines, spirals or points. The attachment means will preferably comprise an open-pattern adhesive network of fibers as described in U.S. Patent 4,573,986 issued to Minetol et al. on March 4, 1986. Exemplary open pattern fiber fasteners include several lines of adhesive filaments twisted into a spiral pattern, as illustrated by the apparatus and method disclosed in U.S. Patent 3,911,173 issued to Sprague, Jr., October 7, 1975; U.S. Patent No. 4,785,996 issued to Ziecker, et al. November 22, 1978; and U.S. Pat. No. 4,842,666, issued to Werenicz on June 27, 1989. Alternatively, the attachment means may include thermal bonds, pressure bonds, ultrasonic bonds, dynamic mechanical bonds, or any other suitable attachment means, or combinations thereof, known in the art. .

The backsheet 23 is impervious to liquids (e.g., menses and / or urine) and is preferably made of a thin plastic film, although other resilient, liquid impervious liquids may also be used.

-21GB 288371 B6 Materials. As used herein, the term "flexible" refers to those materials that are compliant and easily adaptable to the overall shape and contours of the human body. The backsheet 23 prevents the exudates absorbed and retained in the absorbent core from wetting the articles in contact with the sanitary napkin 20, such as panties, pajamas and undergarments. The backsheet 23 may thus consist of a woven or nonwoven material, polymeric films such as thermoplastic films of polyethylene or polypropylene, or composite materials such as a thin wrapped nonwoven material. Preferably, the backsheet is a thermoplastic film having a thickness of from about 0.012 mm to about 0.051 mm.

The backsheet is preferably embossed and / or matte finished to provide a more fabric appearance. The backsheet 23 may further allow vapors to escape from the absorbent core 24 (i.e., have respiratory capability), while still preventing exudates from passing through the backsheet 23. In use, the sanitary napkin 20 may be held in place by any support means (not shown). well known in the art. Preferably, the sanitary napkin is disposed in the wearer's undergarment or panties, and is attached thereto by means of a fastener or adhesive. The adhesive provides a means of attaching the sanitary napkin to the crotch portion of the pantie. Thus, part or all of the exterior of the garment surface 23b of the backsheet 23 is covered with adhesive. Any adhesive or adhesive used in the art for these purposes may be used herein as an adhesive, preferably for a self-adhesive adhesive. Suitable adhesive fasteners are also described in U.S. Pat. No. 4,917,697. Prior to being placed in place, the sanitary napkin has a self-adhesive adhesive typically covered with a removable release cover 37 to protect the adhesive from drying or sticking to a surface other than the crotch region of the panties. Suitable release caps are also described in the above-mentioned U.S. Patent 4,917,697. Any commercially available release caps may be used herein. The sanitary napkin 20 of the present invention is used by removing the release liner and then placing it in the panty such that the adhesive contacts the panty. The adhesive holds the sanitary napkin in position during use. In a preferred embodiment of the present invention, the sanitary napkin has two flaps 34, each adjacent to and extending laterally from the side edge of the absorbent core. The flaps 34 are configured to fold over the edges of the wearer ' s panties in the crotch region so that the flaps may be arranged between the edges of the panties and the thighs of the wearer. These flaps serve at least two purposes. First, the flaps help prevent contamination of the wearer's body and panties by menstrual fluid, preferably by forming a double-wall barrier along the edges of the panties. Second, the flaps are preferably provided on their garment surface with fastening means so that the flaps can be folded back under the panties and attached to the garment facing side of the panties. In this way, the flaps serve to maintain the sanitary napkin properly positioned in the panty. The flaps may be composed of a variety of materials, including materials similar to the topsheet, the backsheet, the fabric, or a combination of these materials. Further, the flaps may be separate elements attached to the main body of the liner, or may include extensions of the top and bottom layers (i.e., unitary). A number of sanitary napkins having flaps suitable or adaptable to use with the sanitary napkins of the present invention are disclosed in U.S. Patent Nos. 4,687,478, entitled "Molded Sanitary Napkin with Flaps", issued to van Tilburg on Aug. 18, 1987; No. 4,589,876, entitled "Sanitary Napkin", issued to van Tilburg on May 20, 1986.

In a preferred embodiment of the present invention, the acquisition layer (s) 25 may be positioned between the topsheet 22 and the absorbent core 24. The acquisition layer 25 may serve several functions including improving the exudate leakage through and into the absorbent core. There are several reasons why improved exudate leakage is important, including ensuring a more even distribution of exudates throughout the absorbent core and allowing the sanitary napkin 20 to be made relatively thin. The leakage in question here may include transporting fluids in one, two or all directions (ie, in the x-y plane and / or z direction). The acquisition layer may be composed of several different materials, including nonwoven or woven structures of synthetic fibers comprising polyester, polypropylene or polyethylene, natural fibers containing cotton or cellulose; mixtures of these fibers or any equivalent materials or combinations thereof. Examples of sanitary napkins having a acquisition layer and a topsheet are described in more detail in U.S. Patent 4,950,264,

No. 288371-6 issued to Osbom and EP617 602 entitled "Absorbent Product Having Melted Layers". In a preferred embodiment, the acquisition layer may be bonded to the topsheet by any conventional means of bonding the layers together, most preferably by fusion bonds, as described in more detail in the aforementioned Cree patent.

In a preferred embodiment, the acquisition layer 25 preferably has a surface energy gradient similar to that of the topsheet 22 and / or the absorbent core 24. In a preferred embodiment, the wearer facing first surface 25a has a relatively low surface energy compared to the absorbent pad contacting surface 25b. Preferably, the surface energy of the first surface 25a of the acquisition layer 25 is greater than the surface energy of the second surface of the upper layer 22. In addition, the second surface 25b of the acquisition layer has a relatively low surface energy compared to the surface energy of the surface 24a facing the body of the absorbent core 24.

Referring now to Figure 16, a further preferred embodiment of the sanitary napkin 120 of the present invention is shown. The insert 120 of FIG. 16 is shown as seen from its first wearer contacting surface 120a. The sanitary napkin 120 comprises a liquid pervious topsheet 12, a liquid pervious backsheet (not shown). bonded to the topsheet 122, and an absorbent core (not shown) disposed between the topsheet 122 and the backsheet, and a acquisition layer (not shown) disposed between the topsheet 122 and the absorbent core. The topsheet 122 preferably comprises a plurality of regions and / or zones, such as a first central region 132, a second region 134 adjacent to and continuous with the first region 132, and a third region 136 adjacent to and continuous with the second region 134. The first central region 132 has a relatively higher surface energy than the upper layer 122 within the adjacent second region 134. Similarly, the first surface of the upper layer 122 within the second region 134 has a relatively higher surface energy than the upper layer 122 within the adjacent third region 136. The topsheet 122 will be driven from the third region 136 towards the second region 134 and the second region 134 towards the first region 132. Accordingly, the fluid will be directed from the third region 136 towards the first region 132 of the topsheet 122 to assist in preventing any fluid leakage across the periphery. 140 given hygienic inserts.

While the first or wearer contacting surface of the topsheet 122 has a surface energy gradient from region to region that may be discrete or continuous, the topsheet 122 will preferably also have an additional surface energy gradient between the first surface and the sidewall portions or intermediate portions of the topsheet. 122. The surface energy of the sidewall parts 134 within the respective regions of the topsheet will be higher than the surface energy of the wearer contacting surface in the first, second and third regions of the topsheet 122. Thus, the topsheet also promotes Z-directional fluid transport similar to structure 80 shown in FIG. Fig. 2.

In some situations, it may be desirable to have a surface energy gradient on the first surface of the topsheet 122 that forces fluid from the first region to the second region and from the second region to the third region. In this embodiment, the first surface of the upper layer 122 within the first region 132 has a relatively lower surface energy than the upper layer 122 within the adjacent second region 134. Similarly, the first surface of the upper layer 122 within the adjacent third region 136. Thus, the fluid deposited on the upper layer 122 This type of surface energy gradient may be desirable in an attempt to fully utilize the absorption capacity of the underlying absorbent core by dispersing body fluids across the first surface of the upper layer, given the The fluids will have a more direct path to the peripheral portions of the underlying absorbent core.

Regions 132, 134, 136 are shown in Figure 16 as having an overall oval configuration. However, these regions can be formed in a wide variety of shapes and sizes such as, for example, rectangular, elliptical, hourglass, dog bone, asymmetric, triangular, circular, or even random shapes and sizes.

-23GB 288371 B6

FIG. 17 shows the sanitary napkin 180 as seen from its first 180a. The sanitary napkin 180 comprises elements or components similar to those of the sanitary napkin 20 shown in Figures 14 and 15 as a liquid-permeable topsheet 182. a liquid-impermeable backsheet associated with the topsheet 182, an absorbent core positioned between the topsheet 182 and the backsheet , and a secondary topsheet or acquisition layer disposed between the topsheet 182 and the absorbent core. The sanitary napkin 180 has a perimeter 190 that is defined by the outer edges of the napkin 180 in which the longitudinal edges or "side edges" 191 and the end edges or "ends" 192. The topsheet 182 comprises a plurality of regions extending generally parallel to the longitudinal axis L The sanitary napkin 180 and comprises a first or central region 184 extending parallel to the longitudinal axis from one end of the sanitary napkin to the other. Adjacent to the first or central region 184 there are a pair of second regions 185, 186 extending substantially parallel to the first region 184. Adjacent to the second regions 185, 186 are a pair of third regions 187, 188. The first region preferably has a relatively high surface energy, compared to 186. Similarly, the second regions 185, 186 have relatively high surface energy compared to the third regions 187, 188.

Alternatively, the first region may have a relatively low surface energy as compared to the second regions 185, 186. The second regions 185, 186 may then have a relatively low surface energy as compared to the third regions 187, 188.

It should be noted that the surface energy characteristics of the regions highlighted in Figures 16 and 17 are in addition to the surface energy gradients and characteristics of the present invention. Accordingly, within one or more of the defined regions in Figures 16 and 17, the surface energy features and characteristics described in Figures 2 and 6-13 are also included.

Figure 18 illustrates an exemplary embodiment of a disposable absorbent article in the form of a diaper 400. As used herein, the term "diaper" refers to an absorbent article generally worn by infants or incontinent persons worn around the lower torso. body of the wearer. However, it will be understood that the invention is also applicable to other absorbent articles, such as incontinence briefs, training pants, diaper pads, sanitary napkins, cosmetic napkins, paper towels and the like. The diaper 400 shown in Figure 18 is a simplified absorbent article. , which could represent a diaper prior to deployment on the wearer. It should be noted that the invention is not limited to the particular type or configuration of diaper shown in Figure 18.

Giant. 18 is a perspective view of the diaper 400 in its flattened, uncontracted state (i.e., without elastic contracting elements) with cut away portions of the structure to more clearly illustrate the respective assembly of the diaper 400. A portion of the diaper 400 contacting the wearer facing the viewer. As shown in FIG. 18, the diaper 400 preferably includes a liquid pervious topsheet 404, a liquid impervious backsheet 402 associated with the topsheet 404; and an absorbent core 406 positioned between the topsheet 404 and the backsheet 402. Additional structural features such as elastic members and fasteners may also be included to secure the diaper in place on the wearer (such as tape tab fasteners). Although the topsheet 404, the backsheet 402, and the absorbent core 406 may be assembled in a variety of well known configurations, a preferred diaper configuration is that generally described in U.S. Patent 3,860,003 (Buell). Alternative preferred disposable diaper configurations are also disclosed in U.S. Patent No. 4,808,178 to Aziz et al., U.S. Patent No. 4,695,278 to Lawson, and U.S. Patent No. 4,816,025 to Foreman.

Giant. 18 illustrates a preferred diaper 400 in which the topsheet 404 and the backsheet 402 are coextensive and have length and width dimensions generally greater than those of the absorbent core 406. The topsheet 404 is bonded to and superimposed on the backsheet 402 to form the perimeter of the diaper 400. This perimeter defines the outer parameter (s) of the diaper 400. The perimeter includes the peripheral ends 401 and the longitudinal edges 403. The topsheet 404 is flexible, soft feeling and non-irritating to the wearer's skin. Further, the topsheet 404 is liquid pervious permitting it to readily penetrate through its thickness. A suitable topsheet 404 may be manufactured from

A wide range of materials such as porous foams, reticulated foams, apertured plastic foils, natural fibers (eg, wood or silk), synthetic fibers (such as polyester or polypropylene), or combinations of natural and synthetic fibers. Preferably, the topsheet 404 is manufactured in accordance with the present invention and has surface energy gradients therein. More preferably, the topsheet 404 is comprised of staple-length polypropylene fibers having a fineness of about 1.5 days. The term "staple-length fibers" refers to those fibers having a length of at least 15.9 mm.

A number of manufacturing techniques can be used to produce the topsheet 404. For example, the topsheet 404 may be canal, nonwoven, carded, centrifugally entangled, and the like. A preferred topsheet 404 has a basis weight of from about 18 to about 25 grams per square meter, a minimum dry tensile force of at least about 400 grams per centimeter. and a wet tensile force of at least 55 grams per centimeter in the transverse direction.

The backsheet 402 is liquid impervious and is preferably made of a thin plastic film, although other resilient liquid impervious materials may also be used. The backsheet 404 prevents the relevant exudates absorbed and retained in the absorbent core 406 from wetting the articles in contact with the diaper 400 as sheets and garment items. Preferably, the backsheet 402 is a polyethylene film having a thickness of from about 0.012 mm to about 0.051 cm, although other flexible liquid impervious materials may be used. As used herein, the term "flexible" refers to those materials that are compliant and easily adaptable to the overall shape and contours of the human body.

The backsheet 402 is preferably embossed and / or matte surface treated to provide a more fabric appearance. Further, the backsheet 402 may allow vapors to escape from the absorbent core 406 while still preventing exudates from passing through the backsheet 402. The size of the backsheet 402 is dictated by the size of the absorbent core 406 and the precise design of the selected diaper.

In a preferred embodiment, the backsheet 402 has a modified hourglass shape extending beyond the absorbent core 406 for a minimum distance of at least 1.3 cm to about 2.5 cm around the entire periphery of the diaper.

The topsheet 404 and the backsheet 402 are bonded together in any suitable manner. The term "bonded" includes those configurations by which the top layer 404 is directly attached to the backsheet 402 by attaching the top layer 404 directly to the backsheet 402 and by which the top layer 404 is indirectly attached to the backsheet 402 by attaching the topsheet 404 to the intermediate layers members that in turn are attached to the backsheet 402.

In a preferred embodiment, the topsheet 404 and the backsheet 402 are directly joined to each other in the diaper periphery by attachment means (not shown) such as an adhesive or any other attachment means known in the art. For example, an arrangement of separate lines or points of adhesive may be utilized by the exemplary adhesive layer, or to attach the topsheet 404 to the backsheet 402. Tape tab fasteners (not shown for clarity) are typically applied to the back waist region of the diaper 402 to provide fastening means for maintaining the diaper on the wearer. The tape tab fasteners may be any well known in the art, such as the fastening tape described in U.S. Pat. No. 3,848,594 (Buell). These tape fasteners or other diaper fasteners are typically applied near the corners of the diaper 400.

The elastic members (not shown for clarity) are disposed adjacent the periphery of the diaper 400, preferably along each longitudinal edge 403, so that the elastic members tend to pull and hold the diaper 400 against the wearer's legs. Alternatively, the elastic members may be disposed adjacent one or both of the end edges 401 of the diaper 400 to secure the waist as well as or rather than the leg cuffs. For example, a suitable belt is disclosed in U.S. Patent 5,515,595 (Kievit et al.). In addition, a method and apparatus suitable for making a disposable diaper with elastically contractible members are described in U.S. Patent 4,081,301 (Buell).

-25GB 288371 B6

Certain elastic members are affixed to the diaper 400 in an elastically retractable state so that, in a normally unstressed configuration, the elastic members effectively retract the diaper 400. The elastic members may be attached in an elastically retractable state in at least two ways. For example, the elastic members may be stretched and secured while the diaper 400 is in an uncontracted condition. Alternatively, the diaper 400 may be contracted, for example, by pleating, and the elastic members may be secured and attached to the diaper 400 while the elastic members are in their relaxed or unstressed condition. The elastic members may extend along a portion of the length of the diaper 400. Alternatively, the elastic members may extend along the entire length of the diaper 400 or any other length suitable to provide an elastically contractible line. The length of the elastic members is dictated by the design of the diaper.

The elastic members may be in a variety of configurations. For example, the width of the elastic members may vary from about 0.25 mm to about 25 mm or more; the elastic members may comprise a single strand of elastic material, or may comprise several, parallel or non-parallel, or the elastic members may be rectangular or curvilinear. Still further, the elastic members may be affixed to the diaper by any of several methods known in the art. For example, the elastic members may be attached to the diaper 400 by ultrasonic bonding, heat and pressure, using a variety of bonding patterns, or the elastic members may simply be glued to the diaper 400.

The absorbent core 406 of the diaper 400 is positioned between the topsheet 404 and the backsheet 402. The absorbent core 406 can be manufactured in a wide variety of sizes and shapes (eg, rectangular, hourglass, asymmetric, and the like).

However, the total absorbent capacity of the absorbent core 406 should be compatible with the intended load for the intended use of the absorbent article or diaper. Further, the respective size and absorbent capacity of the absorbent core 406 may be varied to accommodate wearers ranging from infants to adults.

As shown in Figure 18, the absorbent core 406 comprises a fluid distributing member 408. In a preferred configuration as shown in Figure 18, the absorbent core 406 further preferably comprises a acquisition layer or member 410 in fluid communication with the fluid distributing member. The acquisition layer or member 410 may be comprised of several different materials, including woven or nonwoven structures of synthetic fibers comprising polyester, polypropylene or polyethylene, natural fibers containing cotton, or a member 408 and a member 408. cellulose, mixtures of these fibers or any equivalent materials or combinations thereof.

In use, the diaper 400 is deployed to a wearer by placing a back waist region below the wearer's back and extending the remainder of the diaper 400 between its legs so that the front waist region is positioned across the front of the wearer. The respective tape tabs or other fasteners are then preferably secured to the outwardly facing faces of the diaper 400.

Preparation of exemplary absorbent articles

The following is a description of a suitable method of assembling an exemplary absorbent article comprising the fluid transport structure of the present invention.

Preparation of treated upper layers

SYL-OFF 7048 crosslinker is mixed in 10% added to level to SYL-OFF 7677 Release Coating. This silicone mixture is then freely applied to the paper towel layer commercially available from the Procter & Gambia Company of Cincinnati, Ohio. The particular debt of the towel used does not have a visibly embossed surface pattern. After the mixture has soaked in the paper towel, the excess SYL-OFF is removed by vacuuming with a dry towel,

-26GB 288371 B6 to prevent visible loops of loose silicone material. After this, this towel will be referred to as a "treated towel" for convenience.

The topsheets are cut to the desired size from the topsheet material and strapped to paper towels (Bounty.RTM.) As the carrier material so that the garment facing side of the topsheet is facing the carrier material. The wearer contacting side of the strapped topsheet is then placed on the treated towel. The roller (which is commonly available from the dealership of the technique, known as a printing mold roller, such as the "Speedball" roller by Hunt Mfg. Co) is then gently passed over the back of a paper towel with a strapped top a layer so that the wearer contacting the surface of the topsheet contacts the treated towel. The strapped topsheet is then immediately suspended by the wearer contacting side down in an oven with a non-circulating surface at 60 degrees Celsius and allowed to cure for 10 minutes. To ensure that the cure has been fully cured, the tape on the topsheet can be inspected to ensure that the SYL-OFF mixture is not rubbed.

After curing, the tape and paper towel are removed from the topsheet and the topsheet is cut to the desired size and shape (still larger than the finished absorbent article) from the central (unbanded) portion of the topsheet material. This is done to remove the banded area from the topsheet before the topsheet is weighed to calculate the basis weight of SYL-OFF on the topsheet.

The basis weight of SYL-OFF is determined by subtracting the basis weight of the topsheet material in the uncoated state (grams per square meter) from the basis weight (grams per square meter) of the topsheet material coated. If the basis weight of the unsupported topsheet starting material is not known in advance, the topsheet starting material may be cut to a known size and weighed prior to commencing the surface coating procedure.

In order to obtain different silicone surface weights on the topsheet material, a number of parameters can be measured as desired. These parameters include the roller pressure during its application to the topsheet, the number of passes of the roll over the topsheet material, the viscosity of the silicone material (which can be influenced, for example, by temperature), the saturation level of the treated towel, etc. ready for use on sanitary napkin. The upper layers formed from the initially hydrophobic material are treated with a 0.1% Pegosperse 200 ML solution to render the hydrophilic silicone uncoated surfaces. The garment facing surface of the upper layer is immersed in a pan of suitable size with a Pegosperse 200 ML solution. The topsheet is then immediately suspended with the wearer contacting side up in a non-circulating air furnace at 60 degrees Celsius and allowed to dry. Such an upper layer is then ready to be placed on the sanitary napkin.

Preparing sanitary napkins

The sanitary napkins are assembled as follows. On a silicone coated release paper, a spiral pattern of Findlay H2031 hot melt adhesive is applied in an amount of 0.04 g per 6.45 cm ² . This adhesive layer is transferred to the top (wearer-facing) side of the secondary topsheet by rolling together the secondary topsheet and the surface coated release paper with a hand roller. The secondary topsheet is formed from a nonwoven material known as Hort Howard Airlaid Tissue, class 817, commercially available from Fort Howard Corp. < tb > of Green Bay, Wisconsin. The upper layer is applied to the adhesive side of the secondary upper layer and both are joined together by pushing them together by a hand roller. Two strips of 0.6 cm double-sided tape are applied along both long sides of the polyethylene backsheet. An absorbent core is added to assemble a complete absorbent structure.

The following materials are used for components of the absorbent structure to assemble the absorbent article of FIG. The absorbent article of Fig. 19 (sanitary napkin) is structurally similar to Figs. 14-17, except that it has an overall profile

-27GB 288371 B6 hourglass. The core layer is assembled as follows: a foil of the same material, Fořt Howard, as the secondary topsheet is cut to a final size of 190 mm by 143 mm. A silicone coated release paper containing a spiral pattern of hot melt adhesive Findlay H2031 is applied to Fort Howard at 0.04 grams per 6.45 cm ² . The silicone coated release paper that is used to move the adhesive is left on the Howard Fort and a 190 m by 65 mm template is placed on the central portion of the given layer with longitudinal ends aligned along the longitudinal ends of Forf Howard. Ford Howard is then folded over the template to wrinkle the material, dividing it into three parts. The template is then removed, leaving the glue on the wrinkled Howard Fort. Then, a particle absorbent gel material in the form of Nalco 1180 AGM, in an amount of 0.68 grams per pad, was evenly distributed to the adhesive side of Fort Howard, a nonwoven material. Next, 190 mm 0.6 cm wide double-sided tape is applied to the inner edge of Fort Howard, which is then folded over the folds so that the banded edge is on the top. The resulting storage core has a final dimension of 190 mm by 65 mm, the secondary layer being adhesively bonded to the topsheet.

The storage / core layer is adhesively bonded to the polyethylene backsheet by two strips of 0.6 cm wide double-sided tape.

Then the topsheet and the assembly of the absorbent structure are joined. Then a layer of Teflon® is placed over the assembled structure. The edges of the product are then tightly closed with a suitably shaped die attached to the iron and heated to a temperature above the melting point of the polyethylene topsheet and backsheet. The ironing die is applied to the material by hand pressure to seal (close) the edge. The sanitary napkin is then separated from the material using a pair of hand scissors.

Examples

Example 1

The topsheet was prepared as described above. The starting material was a three-dimensional, macroscopically expanded formed film according to the previously mentioned Radel and Ahr parameters, which are sold for sanitary napkins by the Procter & Gambia Company of Cincinnati, Ohio, as " DRI-WEAVE ". This film had the overall appearance of the film shown in Figure 1 above, and contained a resin-treated surfactant (RIS) to be totally hydrophilic in nature. The topsheet was coated with a silicone on the wearer contacting surface of 0.47 grams per square meter and, according to the procedure above, was incorporated into an absorbent article in a similar sanitary napkin having the overall appearance of the sanitary napkin shown in Figure 19.

Example 2

The topsheet was prepared according to Example 1, except that the silicone surface weight was 1.3 grams per square meter, and was processed into an absorbent article in the form of a sanitary napkin having the overall appearance of the sanitary napkin shown in Figure 19.

Example 3

The topsheet was prepared as described above. The starting material was an unperturbed nonwoven polypropylene fiber structure sold by Veratec of Walpole, Massachusetts, as a P8 diaper topsheet (23 grams per square meter) which was generally hydrophilic in nature. This topsheet was coated with a silicone on the wearer contacting surface at a dose of 0.50 grams per square meter and, in accordance with the procedure above, incorporated into

The absorbent article in the form of a sanitary napkin having the overall appearance of the sanitary napkin shown in Fig. 19.

Example 4

The topsheet was prepared according to Example 3 except that the surface weight of the silicone was 2.7 grams per square meter and was incorporated into the absorbent article in the form of a sanitary napkin having the overall appearance of the sanitary napkin shown in Figure 19.

Example 5

The topsheet was prepared as described above. The starting material was a three-dimensional, macroscopically expanded formed film with microapertures (micro-holes) in accordance with the Curro patent described above. This film had an overall appearance similar to that shown in Figure 10 above. The topsheet was coated with a silicone on the wearer contacting surface at a rate of 0.52 grams per square meter and, in accordance with the above procedure, treated with a surfactant as described above, and in accordance with the above procedure was incorporated into an absorbent article in the form of a sanitary napkin having the overall appearance of the sanitary napkin shown in FIG. 19.

Example 6

The topsheet was prepared according to Example 5, except that the silicone surface weight was 1.08 grams per square meter and was incorporated into the absorbent article in the form of a sanitary napkin having the overall appearance of the sanitary napkin shown in Figure 19.

Methods of analysis

The following exemplary analytical methods have been found to be useful and useful in determining the performance of fluid transfer layers in accordance with the present invention. The analytical methods described herein are preferably performed using a particular standard fluid called artificial menstrual fluid (hereinafter referred to as "AMF"), although similar (same) analytical studies may be performed using other fluids. The formula and preparation of a suitable artificial menstrual fluid is described in the Methods of Testing Patent Application EP 724 420, filed October 21, 1993, by the names of Richards et al.

1. Rate of reception

The uptake rate (or rate) in this material is a measure of the time it takes for a given volume on the surface of the applied fluid to enter or penetrate the topsheet material into the underlying absorbent structure. In this series of tests, it is a measure of time in seconds to completely drain 7.5 ml of an AMF solution with a surface tension of 460-580 N / cm from a 2.54 cm cavity with a depth of 1.58 cm, having a multiple hole pattern in its lowest surface . Other suitable fluid volumes contain 17 ml and 5 ml. The cavity is integrally molded in a 10.16 x 10.16 cm penetration plate that is placed on the finished absorbent article assembled in accordance with the above description, comprising a topsheet for testing. The wearer contacting the topsheet sample surface is oriented upwardly with the front surface area. The electric timer is triggered by contacting a solution of the AMF pair of spaced electrodes in the cavity described above. The timer automatically shuts off when all the AMF solution is drained from the cavity into the absorbent element. Times are given in seconds.

-29GB 288371 B6

2. Dryness

Dryness in this material is a measure of how easily fluid can migrate upwardly to the wearer of the contact surface of the topsheet upon fluid uptake, as well as residual moisture on the topsheet surface. Accordingly, 90 seconds after completion of AMF uptake in the above acceptance test, the penetration plate is removed and a pre-weighed filter paper sample, approximately 12.7 x 12.7 cm, is inserted over the top surface of the topsheet of the absorbent article sample and onto the sample. a predetermined pressure load of about 0.0175 kg / cm ² is applied for 30 seconds. The filter paper is then removed and transported, and the amount of fluid absorbed by the filter paper is called the "surface moisture" of the sample. The results are expressed in grams of fluid absorbed by the filter paper. Other suitable increments of time include 20 minutes after termination of AMF reception. Therefore, as should be understood, a smaller "surface moisture" number is an indication of a drier surface feel. Suitably, "dryness" can be expressed as 1 / surface moisture, resulting in higher dryness values equal to the feel of a drier surface.

3. Masking

The term 'masking' is defined as the difference between the intensity of reflected light between a 'used' or contaminated product and its reflection value before use. The acceptance of a menstrual product depends greatly on the masking effect of its upper layer. In fact, this good camouflage not only provides a cleaner and dry topsheet surface, but also reflects better absorption and less rewet of the product. Masking must be analyzed by measuring the intensity of light reflected from the surface of the product after it has been moistened to quantify and compare the results between products. Light intensity describes the energy of light. The incoming (incident) beam of light (eg sunlight) is reflected by the surface and produces an outgoing (reflected) beam of light that has different energy or intensity. The difference in intensity between the incoming and the outgoing beam is the energy absorbed by the surface. For example, a black surface absorbs considerably more energy or light than a white surface. The energy absorbed by the black surface can be converted into heat. Thus, black cars tend to be warmer in summer than white. The intensity of light depends greatly on the light source. Typically, the light intensity can be characterized by using different gray levels. Thus, white will require a value equal to zero (white = 0) and a black value of 255 (what = 255). Any gray (or light intensity) between these two values will be somewhere between 0 and 255. The sample product for evaluation is analyzed prior to the introduction of any fluid, i.e., in its unused state. The measurement area is defined and a set of measurements is taken. Results from five measurements are averaged. 5 ml of fluid is then poured onto the samples in accordance with the procedure described with respect to the uptake test for moisture measurement. Before removing the penetration plate and subjecting the sample to masking measurements and analysis, the fluid is allowed to stand for 3 minutes to achieve a stable orientation within the sample. A second set of measurements of the same product is then performed using the same identified measurement area. Results from five measurements are averaged. The numerical difference between the initial average value and the average value after use provides quantification in the reflected light difference and hence the surface cleanliness of the product. Small numerical differences reflect a small change from the state before use and, therefore, effective "masking!", While higher differences reflect a larger change from the state before use and, therefore, less effective "masking". The following is a description of suitable components and a suitable method for assessing the effectiveness of masking a fluid transfer structure according to the present invention.

Hardware Components

The scanner used is a traditional HP lip scanner connected to an Apple Macintosh computer. Your computer should have at least 8 MB of RAM to tighten both the scanner software and the NIH display simultaneously. The monitor should then have at least 256 grayscale to operate the software.

-30GB 288371 B6

Software Components

Scanner Software (DeskScan II 2.1)

This software is provided by HP (Hewlett-Packard) and designed to run with the HP lip scanner.

Display NIH version 1.44

This program allows observers to analyze an image and determine the density of any color or gray level, and the intensity of reflected light.

Measurement procedures

The procedure for measuring the sanitary napkin or the like is described in detail below.

Determination of data

Flatness according to a given sample is very important in order to achieve consistent results. At this point, a 30.48 cm long metal ruler, weighing 42.8 grams, is placed over the length of the sanitary napkin to flatten the sample flat to perform the measurement without unduly compressing or breaking the sample.

After the wet samples are scanned, the screen is cleaned with an alcohol-soaked soft cloth. The scanner screen must be very clean, as dirt on the screen may affect the quality of the scanned sample and the measurement.

Using the scanner

The following steps are required to use the HP lip scanner to scan a sample:

To prepare the scanner:

1. Make sure the scanner plug is connected to the computer

2. Turn on the computer

3. Start the scanner

4. Run the Scanner Software (Desk / Scan II 2.1)

To scan impressions:

5. Position the insert at the center of the screen

6. Place the weights (eg metal ruler) on the insert

7. On the program menu, press PREVIEW

8. Choose the type of view you want to have (Choose: “What-White Photography”)

9. Choose your printing method (Choose: Lintronic)

10. Select the desktop you want to scan to a file.

11. Adjust the brightness and contrast

Jas: 114

Contrast: 115

These values must be set so that you always have the same display quality.

12. Make sure you have all the appropriate settings.

13. Press the FINAL button.

The system will ask you to define the name and volume to hold the file. The file should be in TIFF format. Usually this option is preset. Make sure you save the file in TIFF format to open the file in NIH view:

-31GB 288371 B6

The scanner will then scan your insert again, this time slower as it saves the image to a file.

Data evaluation

The following steps describe how to analyze the scanned image:

Analyzing the scanned image using the NIH Customization program view

1. Open the NIH view

2. Customize the program (only when using it for the first time /)

a) OPTIONS menu

Check the gray scale

Preferences: - Undo & Clipboard buffer: set to 1500 (buffer)

- record preference in the FILE menu

b) Menu: ANALYSIS

Options: - check Area and Mean Densitv (area and average density)

- Set Digits right of ... to 1

c) restart the NIH display to make all settings effective.

Measurement

3. Open the calibration file called CALIBRATION.TIFF

4. Open the TIFF file if the system warns you that the UNDO Buffer is too small, add memory by repeating the preferences in step 2a) the measurements for the scanned file will be automatically calibrated (compared) if the CALIBRATION file is open at the same time. TIFF

5. Go to ANALYSIS in the menu and select RESET

6. Start the measurement

(a) choose the area to be measured (you can choose a square window that has about

1.016 x 1.016 cm, which is smaller than the area subjected to the fluidized spillage

b) go to ANALYSIS in the menu and select MEASURE

c) Repeat steps 6 a) and b) for all 5 measurements of the different "square windows" of the sample in the region of interest

d) go to ANALYSIS in the menu and select SHOW RESULTS

7. Close the file without saving

8. Repeat steps 4-7 until the appropriate measurements are completed.

While particular embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover all such changes and modifications within the scope of the present invention.

Claims (10)

PATENT CLAIMS A fluid transport structure having a first surface (90) and a second surface (85) in which fluid passageways (71) are formed between the first surface (90) and the second surface (85), the structure being formed by a shaped film and is further provided with volcanic surface variations, characterized in that the surface energy gradients are defined by regions (98) which are adapted to exert a force on the fluid that is present in the fluid. Contacting the first surface (90) so that the fluid is directed towards the passages (71) to drain it from the first surface (90) to the second surface (85), wherein the regions (98) comprise a material selected from the group of silicone release coatings, modified silicone material, fluorinated materials, petrolatum, latexes, paraffins, surfactants and wetting agents. The fluid transport structure of claim 1, wherein the regions (98) are spaced apart from one another. The fluid transport structure of claim 1, wherein the regions (98) are located at least partially within the fluid flow passage (71). The fluid transport structure of claims 1 to 3, wherein the regions (98) are irregularly distributed on the first surface (90). The fluid transfer structure of claims 1 to 4, wherein the first surface (90) has a first surface energy and the second surface (85) has a second surface energy that is higher than the first surface energy. Structure according to claims 1 to 5, characterized in that the surface energy gradients are defined by the boundaries between said regions (98) and materials having different surface energy characteristics. Structure according to claims 1 to 6, characterized in that the regions (98) are coated with curable silicone as a low surface energy material. Structure according to claim 1, characterized in that the volcanic deviations are provided with at least one micro-hole. The structure of claim 8, wherein the shaped film is a multilayer film having a first layer and a second layer, wherein the second layer has a higher ductility than the first layer and has a higher surface energy than the surface energy of the first layer. A method for producing a fluid transport structure, wherein the structure exhibits a plurality of surface energy gradients, provided with a first surface and a second surface according to claims 1 to 9, characterized in that a plastic film having a first layer and a second layer is first formed, the first layer has a first ductility and a first surface energy, and the second layer exhibits a second ductility that is higher than the first ductility and a second surface energy that is higher than the first surface energy, then this plastic film is fed to the forming structure, then to the plastic film applying a pressure difference to accommodate and break the plastic film to form discrete fluid passages associated with the first surface and the second surface, forming the fluid passages adjacent the first layer to the first surface and the second layer adjacent to the first surface the second surface at.